A distribution in which a variable is distributed like the sum of the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another.
Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.
Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.
A principle of estimation in which the estimates of a set of parameters in a statistical model are those quantities minimizing the sum of squared differences between the observed values of a dependent variable and the values predicted by the model.
Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.
An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
Knowledge, attitudes, and associated behaviors which pertain to health-related topics such as PATHOLOGIC PROCESSES or diseases, their prevention, and treatment. This term refers to non-health workers and health workers (HEALTH PERSONNEL).
Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.
The inhabitants of rural areas or of small towns classified as rural.
Elements of limited time intervals, contributing to particular results or situations.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
Social and economic factors that characterize the individual or group within the social structure.
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.
The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.
One of the MARTIAL ARTS and also a form of meditative exercise using methodically slow circular stretching movements and positions of body balance.
Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.
Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.
The process of breakdown of food for metabolism and use by the body.
Foodstuff used especially for domestic and laboratory animals, or livestock.
The first stomach of ruminants. It lies on the left side of the body, occupying the whole of the left side of the abdomen and even stretching across the median plane of the body to the right side. It is capacious, divided into an upper and a lower sac, each of which has a blind sac at its posterior extremity. The rumen is lined by mucous membrane containing no digestive glands, but mucus-secreting glands are present in large numbers. Coarse, partially chewed food is stored and churned in the rumen until the animal finds circumstances convenient for rumination. When this occurs, little balls of food are regurgitated through the esophagus into the mouth, and are subjected to a second more thorough mastication, swallowed, and passed on into other parts of the compound stomach. (From Black's Veterinary Dictionary, 17th ed)
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Computer-based representation of physical systems and phenomena such as chemical processes.
Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Nutritional physiology of animals.
An ATP-dependent exodeoxyribonuclease that cleaves in either the 5'- to 3'- or the 3'- to 5'-direction to yield 5'-phosphooligonucleotides. It is primarily found in BACTERIA.
An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.
A large family of narrow-leaved herbaceous grasses of the order Cyperales, subclass Commelinidae, class Liliopsida (monocotyledons). Food grains (EDIBLE GRAIN) come from members of this family. RHINITIS, ALLERGIC, SEASONAL can be induced by POLLEN of many of the grasses.
Short-chain fatty acids of up to six carbon atoms in length. They are the major end products of microbial fermentation in the ruminant digestive tract and have also been implicated in the causation of neurological diseases in humans.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.
Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.
Application of statistical procedures to analyze specific observed or assumed facts from a particular study.
Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
Fodder converted into succulent feed for livestock through processes of anaerobic fermentation (as in a silo).
Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A plant species of the family POACEAE. It is a tall grass grown for its EDIBLE GRAIN, corn, used as food and animal FODDER.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
Regular course of eating and drinking adopted by a person or animal.
A statistical analytic technique used with discrete dependent variables, concerned with separating sets of observed values and allocating new values. It is sometimes used instead of regression analysis.
The consumption of edible substances.
The remnants of plant cell walls that are resistant to digestion by the alimentary enzymes of man. It comprises various polysaccharides and lignins.
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
A plant species of the family FABACEAE widely cultivated for ANIMAL FEED.
A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.
Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.
Mathematical procedure that transforms a number of possibly correlated variables into a smaller number of uncorrelated variables called principal components.
Proteins obtained from foods. They are the main source of the ESSENTIAL AMINO ACIDS.
A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.
Inorganic compounds that contain chromium as an integral part of the molecule.
The science and art of collecting, summarizing, and analyzing data that are subject to random variation. The term is also applied to the data themselves and to the summarization of the data.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.
Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.
An indication of the contribution of a food to the nutrient content of the diet. This value depends on the quantity of a food which is digested and absorbed and the amounts of the essential nutrients (protein, fat, carbohydrate, minerals, vitamins) which it contains. This value can be affected by soil and growing conditions, handling and storage, and processing.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).
A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.
The syrup remaining after sugar is crystallized out of SUGARCANE or sugar beet juice. It is also used in ANIMAL FEED, and in a fermented form, is used to make industrial ETHYL ALCOHOL and ALCOHOLIC BEVERAGES.
A quantitative prediction of the biological, ecotoxicological or pharmaceutical activity of a molecule. It is based upon structure and activity information gathered from a series of similar compounds.
An annual legume. The SEEDS of this plant are edible and used to produce a variety of SOY FOODS.
The production of offspring by selective mating or HYBRIDIZATION, GENETIC in animals or plants.
Sequential operating programs and data which instruct the functioning of a digital computer.
An area of recreation or hygiene for use by the public.
Methods developed to aid in the interpretation of ultrasound, radiographic images, etc., for diagnosis of disease.
The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.
A country spanning from central Asia to the Pacific Ocean.
Any aspect of the operations in the preparation, processing, transport, storage, packaging, wrapping, exposure for sale, service, or delivery of food.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
Methods of creating machines and devices.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A family of enzymes that catalyze the exonucleolytic cleavage of DNA. It includes members of the class EC 3.1.11 that produce 5'-phosphomonoesters as cleavage products.
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Continuous frequency distribution of infinite range. Its properties are as follows: 1, continuous, symmetrical distribution with both tails extending to infinity; 2, arithmetic mean, mode, and median identical; and 3, shape completely determined by the mean and standard deviation.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The rate dynamics in chemical or physical systems.
A familial, nontransient HYPOGLYCEMIA with defects in negative feedback of GLUCOSE-regulated INSULIN release. Clinical phenotypes include HYPOGLYCEMIA; HYPERINSULINEMIA; SEIZURES; COMA; and often large BIRTH WEIGHT. Several sub-types exist with the most common, type 1, associated with mutations on an ATP-BINDING CASSETTE TRANSPORTERS (subfamily C, member 8).
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.
Functions constructed from a statistical model and a set of observed data which give the probability of that data for various values of the unknown model parameters. Those parameter values that maximize the probability are the maximum likelihood estimates of the parameters.
Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.
A set of statistical methods for analyzing the correlations among several variables in order to estimate the number of fundamental dimensions that underlie the observed data and to describe and measure those dimensions. It is used frequently in the development of scoring systems for rating scales and questionnaires.
Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.
Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.
The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.
A computer architecture, implementable in either hardware or software, modeled after biological neural networks. Like the biological system in which the processing capability is a result of the interconnection strengths between arrays of nonlinear processing nodes, computerized neural networks, often called perceptrons or multilayer connectionist models, consist of neuron-like units. A homogeneous group of units makes up a layer. These networks are good at pattern recognition. They are adaptive, performing tasks by example, and thus are better for decision-making than are linear learning machines or cluster analysis. They do not require explicit programming.
Any of a group of polysaccharides of the general formula (C6-H10-O5)n, composed of a long-chain polymer of glucose in the form of amylose and amylopectin. It is the chief storage form of energy reserve (carbohydrates) in plants.
The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.
Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.
A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.
The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eye disease.
In statistics, a technique for numerically approximating the solution of a mathematical problem by studying the distribution of some random variable, often generated by a computer. The name alludes to the randomness characteristic of the games of chance played at the gambling casinos in Monte Carlo. (From Random House Unabridged Dictionary, 2d ed, 1993)
Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.
The study of systems which respond disproportionately (nonlinearly) to initial conditions or perturbing stimuli. Nonlinear systems may exhibit "chaos" which is classically characterized as sensitive dependence on initial conditions. Chaotic systems, while distinguished from more ordered periodic systems, are not random. When their behavior over time is appropriately displayed (in "phase space"), constraints are evident which are described by "strange attractors". Phase space representations of chaotic systems, or strange attractors, usually reveal fractal (FRACTALS) self-similarity across time scales. Natural, including biological, systems often display nonlinear dynamics and chaos.
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
Computer-assisted interpretation and analysis of various mathematical functions related to a particular problem.
A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.
The sensory interpretation of the dimensions of objects.
The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)
The study of chance processes or the relative frequency characterizing a chance process.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Increase in BODY WEIGHT over existing weight.
Analysis based on the mathematical function first formulated by Jean-Baptiste-Joseph Fourier in 1807. The function, known as the Fourier transform, describes the sinusoidal pattern of any fluctuating pattern in the physical world in terms of its amplitude and its phase. It has broad applications in biomedicine, e.g., analysis of the x-ray crystallography data pivotal in identifying the double helical nature of DNA and in analysis of other molecules, including viruses, and the modified back-projection algorithm universally used in computerized tomography imaging, etc. (From Segen, The Dictionary of Modern Medicine, 1992)
The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.
A genus of ascarid nematodes commonly parasitic in the intestines of cats and dogs.
The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
Devices or objects in various imaging techniques used to visualize or enhance visualization by simulating conditions encountered in the procedure. Phantoms are used very often in procedures employing or measuring x-irradiation or radioactive material to evaluate performance. Phantoms often have properties similar to human tissue. Water demonstrates absorbing properties similar to normal tissue, hence water-filled phantoms are used to map radiation levels. Phantoms are used also as teaching aids to simulate real conditions with x-ray or ultrasonic machines. (From Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990)
Physical motion, i.e., a change in position of a body or subject as a result of an external force. It is distinguished from MOVEMENT, a process resulting from biological activity.
Products in capsule, tablet or liquid form that provide dietary ingredients, and that are intended to be taken by mouth to increase the intake of nutrients. Dietary supplements can include macronutrients, such as proteins, carbohydrates, and fats; and/or MICRONUTRIENTS, such as VITAMINS; MINERALS; and PHYTOCHEMICALS.
A POSTURE in which an ideal body mass distribution is achieved. Postural balance provides the body carriage stability and conditions for normal functions in stationary position or in movement, such as sitting, standing, or walking.
The physical effects involving the presence of electric charges at rest and in motion.
A plant genus of the family POACEAE. The EDIBLE GRAIN, barley, is widely used as food.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
Any visible result of a procedure which is caused by the procedure itself and not by the entity being analyzed. Common examples include histological structures introduced by tissue processing, radiographic images of structures that are not naturally present in living tissue, and products of chemical reactions that occur during analysis.
A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.
The comparison of the quantity of meaningful data to the irrelevant or incorrect data.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
The measurement of curvature and shape of the anterior surface of the cornea using techniques such as keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing and videokeratography. This measurement is often applied in the fitting of contact lenses and in diagnosing corneal diseases or corneal changes including keratoconus, which occur after keratotomy and keratoplasty.
An illusion of vision usually affecting spatial relations.
Measurement of the various properties of light.
The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.
The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.
Enzymes of the isomerase class that catalyze reactions in which a group can be regarded as eliminated from one part of a molecule, leaving a double bond, while remaining covalently attached to the molecule. (From Enzyme Nomenclature, 1992) EC 5.5.
The science of breeding, feeding and care of domestic animals; includes housing and nutrition.
The act and process of chewing and grinding food in the mouth.
Any device or element which converts an input signal into an output signal of a different form. Examples include the microphone, phonographic pickup, loudspeaker, barometer, photoelectric cell, automobile horn, doorbell, and underwater sound transducer. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)
The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.
The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.
Characteristics or attributes of the outer boundaries of objects, including molecules.
Learning algorithms which are a set of related supervised computer learning methods that analyze data and recognize patterns, and used for classification and regression analysis.
Traumatic injuries to the cranium where the integrity of the skull is not compromised and no bone fragments or other objects penetrate the skull and dura mater. This frequently results in mechanical injury being transmitted to intracranial structures which may produce traumatic brain injuries, hemorrhage, or cranial nerve injury. (From Rowland, Merritt's Textbook of Neurology, 9th ed, p417)
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Seeds from grasses (POACEAE) which are important in the diet.
An infant during the first month after birth.
The characteristic three-dimensional shape of a molecule.
The selecting and organizing of visual stimuli based on the individual's past experience.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.
The systematic identification and quantitation of all the metabolic products of a cell, tissue, organ, or organism under varying conditions. The METABOLOME of a cell or organism is a dynamic collection of metabolites which represent its net response to current conditions.
An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
Asymmetries in the topography and refractive index of the corneal surface that affect visual acuity.
A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories for solving biological problems including manipulation of models and datasets.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Polypeptides produced by the ADIPOCYTES. They include LEPTIN; ADIPONECTIN; RESISTIN; and many cytokines of the immune system, such as TUMOR NECROSIS FACTOR-ALPHA; INTERLEUKIN-6; and COMPLEMENT FACTOR D (also known as ADIPSIN). They have potent autocrine, paracrine, and endocrine functions.
The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)
Recording of the changes in electric potential of muscle by means of surface or needle electrodes.
The physical characteristics and processes of biological systems.
Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)
The properties, processes, and behavior of biological systems under the action of mechanical forces.
Architecture, exterior and interior design, and construction of facilities other than hospitals, e.g., dental schools, medical schools, ambulatory care clinics, and specified units of health care facilities. The concept also includes architecture, design, and construction of specialized contained, controlled, or closed research environments including those of space labs and stations.
Number of individuals in a population relative to space.
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.
The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.
The entities of matter and energy, and the processes, principles, properties, and relationships describing their nature and interactions.
In INFORMATION RETRIEVAL, machine-sensing or identification of visible patterns (shapes, forms, and configurations). (Harrod's Librarians' Glossary, 7th ed)
Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.
A generic concept reflecting concern with the modification and enhancement of life attributes, e.g., physical, political, moral and social environment; the overall condition of a human life.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.
The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
The minimum amount of stimulus energy necessary to elicit a sensory response.
Activities in which participants learn self-defense mainly through the use of hand-to-hand combat. Judo involves throwing an opponent to the ground while karate (which includes kung fu and tae kwon do) involves kicking and punching an opponent.
Computer-assisted study of methods for obtaining useful quantitative solutions to problems that have been expressed mathematically.
A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.
Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.
Passage of food (sometimes in the form of a test meal) through the gastrointestinal tract as measured in minutes or hours. The rate of passage through the intestine is an indicator of small bowel function.
The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.
Assessment of psychological variables by the application of mathematical procedures.
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.
The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Sex differences in the effects of early neocortical injury on neuronal size distribution of the medial geniculate nucleus in the rat are mediated by perinatal gonadal steroids. (1/11846)

Freezing injury to the cortical plate of rats induces cerebrocortical microgyria and, in males but not females, a shift toward greater numbers of small neurons in the medial geniculate nucleus (MGN). The purpose of the current study was to examine a hormonal basis for this sex difference. Cross-sectional neuronal areas of the MGN were measured in male rats, untreated female rats and female rats treated perinatally with testosterone propionate, all of which had received either neonatal cortical freezing or sham injury. Both male and androgenized female rats with microgyria had significantly smaller MGN neurons when compared to their sham-operated counterparts, whereas untreated females with microgyria did not. These differences were also reflected in MGN neuronal size distribution: both male and androgenized female rats with microgyria had more small and fewer large neurons in their MGN in comparison to shams, while there was no difference in MGN neuronal size distribution between lesioned and sham females. These findings suggest that perinatal gonadal steroids mediate the sex difference in thalamic response to induction of microgyria in the rat cortex.  (+info)

Natural history of dysplasia of the uterine cervix. (2/11846)

BACKGROUND: A historical cohort of Toronto (Ontario, Canada) women whose Pap smear histories were recorded at a major cytopathology laboratory provided the opportunity to study progression and regression of cervical dysplasia in an era (1962-1980) during which cervical squamous lesions were managed conservatively. METHODS: Actuarial and Cox's survival analyses were used to estimate the rates and relative risks of progression and regression of mild (cervical intraepithelial neoplasia 1 [CIN1]) and moderate (CIN2) dysplasias. In addition, more than 17,000 women with a history of Pap smears between 1970 and 1980 inclusive and who were diagnosed as having mild, moderate, or severe dysplasia were linked to the Ontario Cancer Registry for the outcome of any subsequent cervical cancers occurring through 1989. RESULTS: Both mild and moderate dysplasias were more likely to regress than to progress. The risk of progression from mild to severe dysplasia or worse was only 1% per year, but the risk of progression from moderate dysplasia was 16% within 2 years and 25% within 5 years. Most of the excess risk of cervical cancer for severe and moderate dysplasias occurred within 2 years of the initial dysplastic smear. After 2 years, in comparison with mild dysplasia, the relative risks for progression from severe or moderate dysplasia to cervical cancer in situ or worse was 4.2 (95% confidence interval [CI] = 3.0-5.7) and 2.5 (95% CI = 2.2-3.0), respectively. CONCLUSION: The risk of progression for moderate dysplasia was intermediate between the risks for mild and severe dysplasia; thus, the moderate category may represent a clinically useful distinction. The majority of untreated mild dysplasias were recorded as regressing to yield a normal smear within 2 years.  (+info)

Low-dose combination therapy as first-line hypertension treatment for blacks and nonblacks. (3/11846)

To assess the efficacy and safety of bisoprolol/6.25-mg hydrochlorothiazide (HCTZ), amlodipine, and enalapril in black and nonblack patients, data from two comparative studies were pooled and subgroup analyses performed. Both studies had similar designs and included all three active treatments. The second study also included a placebo group. Subjects (n = 541) with a sitting diastolic blood pressure of 95-114 mmHg were titrated to achieve a diastolic blood pressure < or = 90 mmHg. The studies included 114 blacks and 427 nonblacks. Results of an intention-to-treat analysis of mean change from baseline after 12 weeks of treatment showed the following: 1) blood pressure was significantly lowered by all three active drugs compared with baseline or placebo; 2) in blacks, bisoprolol/6.25-mg HCTZ resulted in significantly greater reductions of systolic and diastolic blood pressure than enalapril or placebo, but was not significantly different from amlodipine; 3) in nonblacks, bisoprolol/6.25-mg HCTZ resulted in significantly greater reduction of diastolic blood pressure than amlodipine, enalapril, or placebo. The placebo-corrected change in blood pressure was greater for blacks than whites on the bisoprolol/6.25-mg HCTZ combination, but this was not statistically significant. Bisoprolol/6.25-mg HCTZ controlled diastolic blood pressure to < or = 90 mmHg in significantly more patients than enalapril or placebo in blacks and nonblacks. The difference in control rates was not significant versus amlodipine. The incidence of drug-related adverse events was similar between treatments; however, bisoprolol/6.25-mg HCTZ had a lower discontinuation rate due to lack of blood pressure control or adverse experiences in both blacks and nonblacks.  (+info)

Extent and severity of atherosclerotic involvement of the aortic valve and root in familial hypercholesterolaemia. (4/11846)

OBJECTIVE: To compare the frequency of valvar and supravalvar aortic stenosis in homozygous and heterozygous familial hypercholesterolaemia (FH). DESIGN: Analysis of life time cholesterol exposure and prevalence of aortic atherosclerosis in 84 consecutive cases attending a lipid clinic. SETTING: A tertiary referral centre in London. PATIENTS: Outpatients with FH (six homozygous, 78 heterozygous). INTERVENTIONS: Maintenance of lipid lowering treatment. MAIN OUTCOME MEASURES: Calculated cholesterol x years score (CYS) and echocardiographic measurement of aortic root diameter, aortic valve thickness, and transaortic gradient. RESULTS: Four homozygotes with a mean (SD) CYS of 387 (124) mmol/1 x years had severe aortic stenosis (treatment started after seven years of age), whereas the other two had echocardiographic evidence of supravalvar thickening but no aortic valve stenosis (treatment started before three years of age). On multivariate analysis, mean transaortic gradient correlated significantly with CYS (mean = 523 (175) mmol/1 x years) in heterozygotes (p = 0.0001), but only two had severe aortic valve and root involvement. CONCLUSIONS: In patients with familial hypercholesterolaemia, aortic stenosis is common in homozygotes, and aortic root involvement is always present despite the lower CYS than in heterozygotes. It appears to be determined by short term exposure to high cholesterol concentrations in early life. Conversely, aortic root and valve involvement are rare in heterozygotes and occur only with severe, prolonged hypercholesterolaemia, possibly accelerating age related degenerative effects.  (+info)

Amino acid composition of protein termini are biased in different manners. (5/11846)

An exhaustive statistical analysis of the amino acid sequences at the carboxyl (C) and amino (N) termini of proteins and of coding nucleic acid sequences at the 5' side of the stop codons was undertaken. At the N ends, Met and Ala residues are over-represented at the first (+1) position whereas at positions 2 and 5 Thr is preferred. These peculiarities at N-termini are most probably related to the mechanism of initiation of translation (for Met) and to the mechanisms governing the life-span of proteins via regulation of their degradation (for Ala and Thr). We assume that the C-terminal bias facilitates fixation of the C ends on the protein globule by a preference for charged and Cys residues. The terminal biases, a novel feature of protein structure, have to be taken into account when molecular evolution, three-dimensional structure, initiation and termination of translation, protein folding and life-span are concerned. In addition, the bias of protein termini composition is an important feature which should be considered in protein engineering experiments.  (+info)

Prevalence of true vein graft aneurysms: implications for aneurysm pathogenesis. (6/11846)

BACKGROUND: Circumstantial evidence suggests that arterial aneurysms have a different cause than atherosclerosis and may form part of a generalized dilating diathesis. The aim of this study was to compare the rates of spontaneous aneurysm formation in vein grafts performed either for popliteal aneurysms or for occlusive disease. The hypothesis was that if arterial aneurysms form a part of a systemic process, then the rates of vein graft aneurysms should be higher for patients with popliteal aneurysms than for patients with lower limb ischemia caused by atherosclerosis. METHODS: Infrainguinal vein grafting procedures performed from 1990 to 1995 were entered into a prospective audit and graft surveillance program. Aneurysmal change was defined as a focal increase in the graft diameter of 1.5 cm or greater, excluding false aneurysms and dilatations after graft angioplasty. RESULTS: During the study period, 221 grafting procedures were performed in 200 patients with occlusive disease and 24 grafting procedures were performed in 21 patients with popliteal aneurysms. Graft surveillance revealed spontaneous aneurysm formation in 10 of the 24 bypass grafts (42%) for popliteal aneurysms but in only 4 of the 221 grafting procedures (2%) that were performed for chronic lower limb ischemia. CONCLUSION: This study provides further evidence that aneurysmal disease is a systemic process, and this finding has clinical implications for the treatment of popliteal aneurysms.  (+info)

Cryoglobulinaemia and rheumatic manifestations in patients with hepatitis C virus infection. (7/11846)

OBJECTIVES: To investigate the association of cryoglobulinaemia and rheumatic manifestations in Korean patients with hepatitis C virus (HCV) infection. METHODS: Forty nine Korean patients with HCV infection were recruited. The prevalence, concentration, and type of cryoglobulin (by immunofixation), rheumatoid factor (RF), antinuclear antibody (ANA), and various rheumatological symptoms were investigated and HCV genotype was determined by polymerase chain reaction with genotype specific primer. RESULTS: The prevalence of cryoglobulin was 59% in Korean HCV patients and the concentration of cryoglobulin was 9.8 (7.9) g/l (mean (SD)). The type of cryoglobulinaemia was identified in 23 (80%) of 29 HCV patients with cryoglobulinaemia and they were all type III. There were no differences in age, sex, history of operation and transfusion, proportion of liver cirrhosis between the patients with cryoglobulinaemia and those without cryoglobulinaemia. The frequencies of RF and ANA were 14% and 3.4% respectively in HCV patients with cryoglobulinaemia. There was no difference in HCV genotype between the patients with cryoglobulinaemia and those without cryoglobulinaemia. Clinical features of HCV patients were as follows: arthralgia/arthritis (35%), cutaneous manifestation (37%), Raynaud's phenomenon (8%), paresthesia (44%), dry eyes (22%), dry mouth (10%), oral ulcer (33%), and abdominal pain (14%). However, these rheumatological symptoms did not differ between the two groups. CONCLUSION: Although the rheumatological symptoms were not different between HCV patients with and without cryoglobulinaemia, HCV patients showed various rheumatological manifestations. These result suggests that HCV infection could be included as one of the causes in patients with unexplained rheumatological symptoms.  (+info)

Fetal tachycardias: management and outcome of 127 consecutive cases. (8/11846)

OBJECTIVE: To review the management and outcome of fetal tachycardia, and to determine the problems encountered with various treatment protocols. STUDY DESIGN: Retrospective analysis. SUBJECTS: 127 consecutive fetuses with a tachycardia presenting between 1980 and 1996 to a single tertiary centre for fetal cardiology. The median gestational age at presentation was 32 weeks (range 18 to 42). RESULTS: 105 fetuses had a supraventricular tachycardia and 22 had atrial flutter. Overall, 52 fetuses were hydropic and 75 non-hydropic. Prenatal control of the tachycardia was achieved in 83% of treated non-hydropic fetuses compared with 66% of the treated hydropic fetuses. Digoxin monotherapy converted most (62%) of the treated non-hydropic fetuses, and 96% survived through the neonatal period. First line drug treatment for hydropic fetuses was more diverse, including digoxin (n = 5), digoxin plus verapamil (n = 14), and flecainide (n = 27). The response rates to these drugs were 20%, 57%, and 59%, respectively, confirming that digoxin monotherapy is a poor choice for the hydropic fetus. Response to flecainide was faster than to the other drugs. Direct fetal treatment was used in four fetuses, of whom two survived. Overall, 73% (n = 38) of the hydropic fetuses survived. Postnatally, 4% of the non-hydropic group had ECG evidence of pre-excitation, compared with 16% of the hydropic group; 57% of non-hydropic fetuses were treated with long term anti-arrhythmics compared with 79% of hydropic fetuses. CONCLUSIONS: Non-hydropic fetuses with tachycardias have a very good prognosis with transplacental treatment. Most arrhythmias associated with fetal hydrops can be controlled with transplacental treatment, but the mortality in this group is 27%. At present, there is no ideal treatment protocol for these fetuses and a large prospective multicentre trial is required to optimise treatment of both hydropic and non-hydropic fetuses.  (+info)

Definition of Chi-square distribution in the Legal Dictionary - by Free online English dictionary and encyclopedia. What is Chi-square distribution? Meaning of Chi-square distribution as a legal term. What does Chi-square distribution mean in law?
Hello, I am trying to understand some results I got (see below) and any assistance will be greatly appreciated. I have run a number of conditional logit models (with cluster-adjusted robust SEs) and usually, if you get a greater Wald chi-square value, you also get a greater pseudo r-square. But the models below are strange in that the first one has a great pseudo r-square value while the second one has a greater Wald chi-square value. The only thing that changes from one model to the next are the third and fourth variables starting from the bottom (i.e., in the second model, a_lneuclkm and m_lneuclkm have been substituted by a_lneuclmins and m_lneuclmins). Does anyone have any information about how the Wald test statistic is calculated so that I can relate this to how the log-likelihood and the pseudo r-square are calculated (and work out why they might be behaving in this way)? Thanks very much, Lucia. Model 1 . clogit choice commerc100 nostations popdens unemp10 imdincome imdhealth ...
Im trying to see if there is a dependent relationship between whether a school is public or private and its student-teacher ratio. Im not sure if I can use a chi square test for this because there is like a 6 to 1 ratio between the amounts of public and private schools that I have for my data (way more public schools). Can I chi square test still work ...
Determining significance of chi square. If we wish to reject Ho at the .05 level, we will determine if our value of chi square is greater than the critical value of chi square that cuts off the upper 5% of the distribution at our particular degrees of freedom value. If our value of chi square from the formula is greater than the critical value of chi square, we reject Ho and conclude that the obtained frequencies differ from the expected frequencies more than would be predicted by chance. ...
Join Barton Poulson for an in-depth discussion in this video Single categorical variable: One-sample chi-squared test, part of SPSS Statistics Essential Training
A JavaScript that computes Chi-square statistic as a measuring tool and decision criterion for goodness of-fit distributions of observed frequencies.
where L is a matrix of coefficients for the linear hypotheses, and c is a vector of constants. The Wald chi-square statistic for testing ...
Used for comparing frequencies (counts) of nominal or ordinal level data for two samples across two or more subgroups displayed in a crosstabulation table. More common and more flexible than z-tests of proportions ...
Free chi-square distribution calculator computes cumulative probability. Fast, easy, accurate. An online chi-square statistical table. Includes sample problems.
Computes the continuous non-central chi-squared cumulative distribution function (CDF), the probability that a non-central chi-squared-distributed variate takes on a value less than or equal to the quantile of the random variable. A non-central chi-squared variate with k degrees of freedom and nonce
Get Online Statistics Help on chi-square assignment help and chi-square Homework help from best experts of Courseworktutors Inc at affordable prices.
The Chi-Square test of Independence is used to determine if there is a significant relationship between two nominal (categorical) variables.
Solved: I want to integral this function (1-chi-square(x/2,df=10))**5 by the chi-square( x, df=10), so I write the code below. However, the error
Understanding chi-square, regression and ANOVA outputs from spss! Categorical variations and regression, what really matter in the outputs?
I need help identifying variables and conducting t-tests and chi-squared tests and how to use Excel to calculate the data. Identify three continuous and three discrete variables and describe their distribution numerically (e.g.,.
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Friedmans test is a nonparametric test for treatment differences in a randomized complete block design. Each block of the design may be a subject or a homogeneous group of subjects. If blocks are groups of subjects, the number of subjects in each block must equal the number of treatments. Treatments are randomly assigned to subjects within each block. If there is one subject per block, then the subjects are repeatedly measured once under each treatment. The order of treatments is randomized for each subject. In this setting, Friedmans test is identical to the ANOVA (row means scores) CMH statistic when the analysis uses rank scores (SCORES=RANK). The three-way table uses subject (or subject group) as the stratifying variable, treatment as the row variable, and response as the column variable. PROC FREQ handles ties by assigning midranks to tied response values. If there are multiple subjects per treatment in each block, the ANOVA CMH statistic is a generalization of Friedmans test. The data ...
A standalone Windows program that calculates the chi-square statistic for 2x2 to 10x10 contingency tables. Also calculates the contingency coefficient, phi, and
1. What is the null and alternative hypothesis to test whether a person?s educational level is dependent or independent of his or her race/gender classification? 2. Looking at the p-value, would you accept or reject the null.
The most unbiased point estimate for the population variance σ2 is the sample-variance (s2) and the point estimate for the population standard deviation σ is the sample standard deviation (s). We use a Chi-square distribution to construct confidence intervals for the variance and standard distribution. If the process or phenomenon we study generates a Normal random variable, then computing the following random variable (for a sample of size n , 1) has a Chi-square distribution ...
Chi-square analysis is a statistical method to calculate the probability that two dichotomous variables within a sample or population are related. This ...
This activity looks at the distribution of heart attacks over the days of the week. It starts out looking at those who are employed, but there is an extra data set that looks at those who are not employed. Comments from participants at our Morro Bay workshop are left in to see the discussion between statisticians and biologists as we try to shape activities that get biologists to think statistically.. Chi-square test. ...
CHI-Squared Test of Independence Minhaz Fahim Zibran Department of Computer Science University of Calgary, Alberta, Canada. Abstract Chi-square (X 2 ) test is a nonparametric
From the image above, it can be seen that the most contributing cells to the Chi-square are Wife/Laundry (7.74%), Wife/Main_meal (4.98%), Husband/Repairs (21.9%), Jointly/Holidays (12.44%).. These cells contribute about 47.06% to the total Chi-square score and thus account for most of the difference between expected and observed values.. This confirms the earlier visual interpretation of the data. As stated earlier, visual interpretation may be complex when the contingency table is very large. In this case, the contribution of one cell to the total Chi-square score becomes a useful way of establishing the nature of dependency ...
Today s lecture Lecture 6: Dichotomous Variables & Chi-square tests Sandy Eckel Dichotomous Variables Comparing two proportions using 2 2 tables Study Designs Relative risks, odds ratios
Non-normal is not a specific distribution. If you really want to know how much difference it would make you must be specific about the distribution - and if you are specific then you can calculate the difference yourself ...
If youre working on any statistical problem involving chi-square SPSS is the program you need. Get to grips with using the versatile and helpful program.
nbsp1.which of following does the term observed frequency refer to?nbspa frequencies computed from the null hypothesisb, Hire Statistics and Probability Expert, Ask Statistics Expert, Assignment Help, Homework Help, Textbooks Solutions
Also called Parrys disease. Plummers disease is the cause of about 5% of cases of hyperthyroidism. It does not usually remit after a course of antithyroid drugs. Plummers condition characterized by marked enlargement of the thyroid gland (goitre), firm thyroid nodules, and mild overproduction of thyroid hormone.. Plummers disease, which usually occurs in older people, is of unknown etiology. Its symptoms resemble those of Graves disease, a condition believed to be an autoimmune disorder.. Also known as Graves disease, thyrotoxicosis, toxic diffuse goiter, toxic nodular goiter and Basedows disease. Hyperthyroidism is a condition marked by excessive production of thyroid hormones that results in multiple-system abnormalities ranging from mild to severe hormonal imbalances.. The physical examination may reveal a rapid and/or irregular heart beat, warm, thin, moist skin over most of the body. Other physical signs which can occur in certain people are eyelid lag, eyelid retraction, abnormal ...
Abstract: Many researchers in the health field use the chi-square statistic to identify associations between variables. This edition of research notes will demonstrate that the odds ratio may be a preferred analysis to yield more useful and meaningful results. In epidemiological and health contexts, the outcome variable is often discrete, taking on two (or more) possible scores. Application of odds ratios and logistic models in epidemiology and medical research ...
For a correctly specified model, the Pearson chi-square statistic and the deviance, divided by their degrees of freedom, should be approximately equal to one. When their values are much larger than one, the assumption of binomial variability might not be valid and the data are said to exhibit overdispersion. Underdispersion, which results in the ratios being less than one, occurs less often in practice. When fitting a model, there are several problems that can cause the goodness-of-fit statistics to exceed their degrees of freedom. Among these are such problems as outliers in the data, using the wrong link function, omitting important terms from the model, and needing to transform some predictors. These problems should be eliminated before proceeding to use the following methods to correct for overdispersion. ...
The Chi-Square distribution is used in the chi-square tests for goodness of fit of an observed distribution to a theoretical one and the independence of two criteria of classification of qualitative data. It is also used in confidence interval estimation for a population standard deviation of a normal distribution from a sample standard deviation. The Chi-Square distribution is a special case of the Gamma distribution [link to gamma]. PDF ...
This statistic is useful if you have two ordered variables, going from Low to High. They dont need to be interval: all you need to do is order it; in the case of which one is bigger, and which one is smaller. If you have people who are Temp; People who are hourly; exempt employees; profit-sharing; you could code these things as 1,2,3,4, but would it make sense to run a correlation looking for a linear relationship between them? Not really. But it would make sense at a job level, if you were able to put these in a specific order. Take an attitude measure: Strongly Agree (1) ,-? (2) -,Strongly Disagree (3) - there arent necessarily equal intervals here, but what were interested in is whether there is an ordinal trend, such as, are people higher in the job level more likely to agree? Example 2 In a 2x2 table like in Example 3 what test would you apply? Chi Square Test of Independence. If you ran a χ^2 on this table, ...
is an approximation which is valid only for large values of n, and is therefore only meaningful when calculated from a large number of independent experiments.. In this implementation, the Chi-Square distribution is calculated for the list of values given as argument to the random-test procedure and expressed as an absolute number and a percentage which indicates how frequently a truly random sequence would exceed the value calculated.. The percentage can be interpreted as the degree to which the sequence tested is suspected of being non-random. If the percentage is greater than 99% or less than 1%, the sequence is almost certainly not random. If the percentage is between 99% and 95% or between 1% and 5%, the sequence is suspect. Percentages between 90% and 95% and 5% and 10% indicate the sequence is almost suspect.. ...
When dealing with two categorical variables, a two-way table is a helpful way to display this data. Find out what is a two-way table.
The purpose of this study was to compare the degree to which children and adolescents with and without visual impairments (VIs) met national physical activity, screen-time, and sleep guidelines. This observational, cross-sectional analysis of the 2016 National Survey of Childrens Health focused on children (age 6-12 yr) and adolescents (age 13-17 yr) with and without VIs. The sample included 241 (weighted n = 472,127) and 17,610 (weighted n = 28,249,833) children, and 255 (weighted n = 505,401) and 17,417 (weighted n = 20,071,557) adolescents with and without VIs, respectively. Chi-square statistics were computed to examine the degree to which participants with and without VIs met health-behavior guidelines. Children (p = .02) with VIs were less likely to meet screen-time guidelines, but adolescents with VIs were not (p = .87). VI status was not associated with the likelihood of meeting physical activity or sleep guidelines (p , .05). Low numbers of children and adolescents with and without VIs ...
The purpose of this study was to compare the degree to which children and adolescents with and without visual impairments (VIs) met national physical activity, screen-time, and sleep guidelines. This observational, cross-sectional analysis of the 2016 National Survey of Childrens Health focused on children (age 6-12 yr) and adolescents (age 13-17 yr) with and without VIs. The sample included 241 (weighted n = 472,127) and 17,610 (weighted n = 28,249,833) children, and 255 (weighted n = 505,401) and 17,417 (weighted n = 20,071,557) adolescents with and without VIs, respectively. Chi-square statistics were computed to examine the degree to which participants with and without VIs met health-behavior guidelines. Children (p = .02) with VIs were less likely to meet screen-time guidelines, but adolescents with VIs were not (p = .87). VI status was not associated with the likelihood of meeting physical activity or sleep guidelines (p , .05). Low numbers of children and adolescents with and without VIs ...
To understand which instruments and symptoms best discriminate episodes, canonical discriminant analyses (CDAs) were conducted. These statistical procedures find patterns of canonical correlation between features that separate scores and items according to a dependent variable. In other words, CDA is a type of regression that allows identification of which items or instruments are better than others to separate groups. Three indexes are used to interpret CDA: chi-square, Wilks lambda, and the standardized canonical coefficient (SCC). The chi-square statistic reveals whether the variable is able to discriminate groups in a significant manner (p < 0.05). Wilks lambda tests the extent to which a variable contributes to discrimination: the closer to 0 the index, the higher the extent to which the variable contributes to separate groups. Finally, the SCC ranks the importance of variables to separate groups; i.e., the higher the coefficient, the more important the variable. SCC and Wilks lambda are ...
The paper presents a new concept of parallel bivariate marginal distribution algorithm using the stepping stone based model of communication with the unidirectional ring topology. The traditional migration of individuals is compared with a newly proposed technique of probability model migration. The idea of the new xBMDA algorithms is to modify the learning of classic probability model (applied in the sequential BMDA). In the first strategy, the adaptive learning of the resident probability model is used. The evaluation of pair dependency, using Pearsons chi-square statistics is influenced by the relevant immigrant pair dependency according to the quality of resident and immigrant subpopulation. In the second proposed strategy, the evaluation metric is applied for the diploid mode of the aggregated resident and immigrant subpopulation. Experimental results show that the proposed adaptive BMDA outperforms the traditional concept of individual migration ...
Methods: This is a prospective study of 119 patients admitted with hip fracture during a 14 month period. Patients were divided into two groups, diabetics (n=19) and non-diabetics (n=100). Information was collected including patient demographics, functional status, medical co-morbidities (using the CCI - Charlson Co-morbidity Index tool), previous history of fractures, vitamin D level and supplementation, fracture type and duration to surgery. Immediate post-operative complications, rate of 30-day mortality and length of rehabilitation stay were analysed and compared between the two groups. The validity of the results was assessed using the Chi-square statistic for categorical variables and the t-test for continuous variables using the Systat program. Results: The mean age was significantly different for each group with diabetics presenting 6 years earlier (age 77.5 versus 83.5, p = 0.03).The CCI score had a bimodal distribution in diabetics. Other baseline characteristics were comparable ...
AIM: To describe the endodontic status amongst middle-aged and elderly women longitudinally and cross-sectionally over 24 years. METHODOLOGY: A random sample of 1462 women 38, 46, 50, 54 and 60 years old, living in Göteborg, Sweden, were sampled in 1968 for medical and dental examinations with a participation rate of 90.1%. The same women were re-examined in 1980 and 1992 together with new 38- and 50-year-old women. The dental examination consisted of questionnaires, clinical and panoramic radiological survey (OPG). The number of teeth, number of root filled teeth (RF) and number of teeth with periapical radiolucencies (PA) were registered. The RF and PA ratios were calculated. Cross-sectional data were analysed by means of anova and longitudinal data by a general linear model for repeated measures. Sample prevalences were compared and statistical inferences were made with the chi-squared test. In all analysis, the confidence interval (CI) regarded mean difference between groups (95% CI). ...
I want to calculate chi square test of goodness of fit to test, Sample coming from Poisson distribution. please copy this script in R & run the script The R script is as follows ########################## start ######################################### No_of_Frouds,- c(4,1,6,9,9,10,2,4,8,2,3,0,1,2,3,1,3,4,5,4,4,4,9,5,4,3,11,8,12,3,10,0,7) N ,- length(No_of_Frouds) # Estimation of Parameter lambda,- sum(No_of_Frouds)/N lambda pmf ,- dpois(i, lambda, log = FALSE) step_function ,- ppois(i, lambda, lower.tail = TRUE, log.p = FALSE) # Chi-Squared Goodness of Fit Test # Ho: The data follow a Poisson distribution Vs H1: Not Ho Frauds ,- c(1:13) counts,- c(2,3,3,5,7,2,1,1,2,3,2,1,1,0) # Observed frequency Expected ,-c(0.251005528,1.224602726,2.987288468,4.85811559,5.925428863,5.7817821 03,4.701348074,3.276697142,1.998288788,1.083247457,0.528493456,0.2344006 79,0.095299266,0.035764993) chisq.test(counts, Expected, simulate.p.value =FALSE, correct = FALSE) ######################### end ...
Preface xiii Part I. Summarizing Data 1. 1. Data Organization 3. 1.1 Introduction 3. 1.2 Consideration of Variables 4. 1.3 Coding 15. 1.4 Data Manipulations 18. 1.5 Conclusion 20. 2. Descriptive Statistics for Categorical Data 33. 2.1 Introduction 33. 2.2 Frequency Tables 35. 2.3 Crosstabulations 37. 2.4 Graphs and Charts 45. 2.5 Conclusion 50. 3. Descriptive Statistics for Continuous Data 63. 3.1 Introduction 63. 3.2 Frequencies 64. 3.3 Measures of Central Tendency 70. 3.4 Measures of Dispersion 73. 3.5 Standardized Scores 79. 3.6 Conclusion 88. Part II. Statistical Tests 101. 4. Evaluating Statistical Significance 103. 4.1 Introduction 103. 4.2 Central Limit Theorem 104. 4.3 Statistical Significance 107. 4.4 The Roles of Hypotheses 115. 4.5 Conclusion 119. 5. The Chi-Square Test: Comparing Category Frequencies 125. 5.1 Introduction 125. 5.2 The Chi-Square Distribution 126. 5.3 Performing Chi-Square Tests 130. 5.4 Post Hoc Testing 143. 5.5 Confidence Intervals 146. 5.6 Explaining Results of the ...
A distribution in which a variable is distributed like the sum of the the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another. ...
The p-value of the test is 8.80310^{-7}, which is less than the significance level alpha = 0.05. We can conclude that the colors are significantly not commonly distributed with a p-value = 8.80310^{-7}. Note that, the chi-square test should be used only when all calculated expected values are greater than 5.. ...
I have a question regarding the relationship between the value of Chi square and df in determining the goodness-of-fit in a model derived from multivariate logistic regression. If the N= 290, Chi square =26.57, p=0.003 in a model with 16 variables (df is not reported), can one tell if this is ...
Since the chi-square test statistic 2.30 does not meet or exceed the critical value of 9.488, you cannot conclude there is a statistically significant difference among the assembly lines in the observed frequencies of defective parts ...
Perform crosstabs with multiple field as columns and percentages with Chi-Square on your Microsoft Access data with Total Access Statistics
Enter frequencies that are non-negative whole numbers in each of the four cells. Do not try to enter totals; totals are automatically calculated.. Use Fisher exact test when cell frequencies in a 2 x 2 table are small, so chi-square approximation is not suitable. ...
I have always learned that if you have a contingency table that violates the chi square assumption of more than 20% of cells having expected count less...
displaystyle \chi ^{2}=wy^{2}\;\left[=193,\chi ^{2}(p=0.001,\;df=1)=10.8\right]}. follows the chi-square distribution with d. f ... displaystyle \chi ^{2}}. test calculating χ. 2. =. (. a. d. −. b. c. ). 2. N. A. B. C. D. (. =. 336. ,. for data in Table 3; P ... displaystyle \chi ^{2}={\frac {(ad-bc)^{2}N}{ABCD}}\;(=336,{\text{ for data in Table 3; }}P,0.001).}. where d. f. =. 1. {\ ... is the correlation coefficient between pairs of loci, usually expressed as its square, r. 2. {\displaystyle r^{2}}. [6] ...
Typically the square of the difference is compared to a chi-squared distribution. ... Recalling that a quadratic form of normal distribution has a Chi-squared distribution: n. (. R. θ. ^. n. −. r. ). ′. [. R. V. R ... chi _{Q}^{2}}. Rearranging n finally gives: (. R. θ. ^. n. −. r. ). ′. [. R. (. V. /. n. ). R. ′. ]. −. 1. (. R. θ. ^. n. −. r ... multiplying by R has distribution: R. n. (. θ. ^. n. −. θ. ). =. n. (. R. θ. ^. n. −. r. ). →. D. N. (. 0. ,. R. V. R. ′. ). {\ ...
"On limiting distribution laws of statistics analogous to Pearson's chi-square". Statistics: A Journal of Theoretical and ... Z. W. Birnbaum; I. Vincze (1973). "Limiting Distributions of Statistics Similar to Student's". Annals of Statistics. 1 (1973): ... Vincze, István (1996). "Cramér-Rao type inequality and a problem of mixture of distributions". Mathematical Institute, Slovak ... empirical distribution, Cramér-Rao inequality, and information theory. Considered by many, as an expert in theoretical and ...
This test yields a Wald statistic which follows a chi-square distribution. In this case the null hypothesis being tested is H0 ... G2 approximately follows a chi square distribution, especially with larger samples. Therefore, it is evaluated by the degrees ... Determination of DIF is made by evaluating the obtained chi-square statistic with 2 degrees of freedom. Additionally, parameter ... In this case, the absence of DIF is determined by the fact that the conditional probability distribution of Y is not dependent ...
has a chi square distribution with n − 1 degrees of freedom and thus its square root, n. −. 1. s. /. σ. {\displaystyle {\sqrt { ... where the correction factor c4(n) is the scale mean of the chi distribution with n − 1 degrees of freedom, μ. 1. (. n. −. 1. ) ... has a chi distribution with n − 1 degrees of freedom. Consequently, calculating the expectation of this last expression and ... Other distributions[edit]. In cases where statistically independent data are modelled by a parametric family of distributions ...
"A note on the distribution of the sum of chi-squares", Sankhya, 7 (1945), 27 - 28. "On some analogues of the amount of ... Distance between statistical distributions had been addressed in 1936 by Mahalanobis, who proposed the D2 metric, now known as ... Inst., 33, Part II (1951). "On some uses of the t-distribution in multivariate analysis", Sankhya, 12 (1952), 89 - 104. "Notes ... "On a measure of divergence between two statistical populations defined by their probability distributions", Bull. Cal. Math. ...
The statistic is approximately from the t-distribution since we have an approximation of the chi-square distribution. This ... Welch's t-test remains robust for skewed distributions and large sample sizes. Reliability decreases for skewed distributions ... Student's t-test assumes that the sample means (test statistics) of two population distributions being compared are normally ... Welch's t-test is designed for unequal sample distribution variance, but the assumption of normally distributed sample is ...
Curran, P. J., Bollen, K. A., Paxton, P., Kirby, J., & Chen, F. (2002). The noncentral chi-square distribution in misspecified ...
... chi-square distribution with zero degrees of freedom concentrates all probability at zero. All of this leaves open the question ... The chi-squared distribution with n degrees of freedom is the probability distribution of the sum X 1 2 + ⋯ + X n 2 {\ ... The noncentral chi-squared distribution with zero degrees of freedom and with noncentrality parameter μ is the distribution of ... then the sum of squares above has a non-central chi-squared distribution with n degrees of freedom and "noncentrality parameter ...
Sawilowsky, S. (1985). "A comparison of random normal scores test under the F and Chi-square distributions to the 2x2x2 ANOVA ... Treat the mean for each group as a score, and compute the variability (again, the sum of squares) of those three scores. When ... Under the truth of the null hypothesis, the sampling distribution of the F ratio depends on the degrees of freedom for the ... or sum of squares) of scores on some dependent variable will be the same within each group. When divided by the degrees of ...
Chi-square test, and T-Test. The program was offered in both disk and cassette stand-alone versions, as well as in a compendium ... Calculations performed by the program included mean, variance, standard deviation, Pearson correlation, normal distribution, ...
... the sums-of-squares no longer have scaled chi-squared distributions. Comparison of sum-of-squares with degrees-of-freedom is no ... The residual sum-of-squares ‖ y − H y ‖ 2 {\displaystyle \,y-Hy\,^{2}} has a generalized chi-squared distribution, and the ... the sums of squares have scaled chi-squared distributions, with the corresponding degrees of freedom. The F-test statistic is ... these sums-of-squares no longer have (scaled, non-central) chi-squared distributions, and dimensionally defined degrees-of- ...
When assessed upon a chi-square distribution, nonsignificant chi-square values indicate very little unexplained variance and ... chi _{s-p}^{2},} chi-square distribution with degrees of freedom equal to the difference in the number of parameters estimated ... to the square of the standard error of the coefficient and is asymptotically distributed as a chi-square distribution. W j = β ... one simply compares the deviance of the predictor model with that of the null model on a chi-square distribution with a single ...
... the square root of the median of a chi-squared distribution with 3 degrees of freedom.. ... The left panel shows the joint distribution of X 1 {\displaystyle X_{1}} and Y 2 {\displaystyle Y_{2}} ; the distribution has ... The right panel shows the joint distribution of Y 1 {\displaystyle Y_{1}} and Y 2 {\displaystyle Y_{2}} ; the distribution has ... This furnishes two examples of bivariate distributions that are uncorrelated and have normal marginal distributions but are not ...
... chi-square); William Gosset (1876-1937) (Student's t-distribution); Ronald Fisher (1890-1962) (Analysis of variance); Frank ... "Paterson, Rex (1955). Fertilizer Distribution - Problems of Corrosion Prevention on the Farm. The International Fertilizer ...
Royen worked mainly on probability distributions, in particular multivariate chi-squares and gamma distributions, to improve ... Thomas Royen: A simple proof of the Gaussian correlation conjecture extended to some multivariate gamma distributions, in: Far ... Royen, T. (2014). "A simple proof of the Gaussian correlation conjecture extended to multivariate gamma distributions". arXiv: ... Supplemented by Royen, Thomas (2015). "Some probability inequalities for multivariate gamma and normal distributions". arXiv: ...
The residual sum-of-squares ‖. y. −. H. y. ‖. 2. {\displaystyle \,y-Hy\,^{2}}. has a generalized chi-squared distribution, and ... then the residual sum of squares has a scaled chi-squared distribution (scaled by the factor σ. 2. {\displaystyle \sigma ^{2}} ... the sums-of-squares no longer have scaled chi-squared distributions. Comparison of sum-of-squares with degrees-of-freedom is no ... In the example above, the residual sum-of-squares is ∑. i. =. 1. n. (. X. i. −. X. ¯. ). 2. =. ‖. X. 1. −. X. ¯. ⋮. X. n. −. X ...
Vassily Voinov, statistician, major developer of extensions of khi-square distributions KIMEP has active partnerships with more ... The 325-square-meter facility includes a basketball court, two fitness rooms and a yoga studio. All the technology is state-of- ...
The distribution of the chi-square statistics for a given allele that is suspected to be associated with a given trait can then ... using a set of anonymous genetic markers to estimate the effect of population structure on the distribution of the chi-square ... be compared to the distribution of the same statistics for an allele that is expected not to be related to the trait. The ...
The exponential distribution, Erlang distribution, and chi-square distribution are special cases of the gamma distribution. ... If α is a positive integer (i.e., the distribution is an Erlang distribution), the cumulative distribution function has the ... The gamma distribution is a special case of the generalized gamma distribution, the generalized integer gamma distribution, and ... see also Rayleigh distribution and Rician distribution. In oncology, the age distribution of cancer incidence often follows the ...
The sum of squares of the statistical errors, divided by σ2, has a chi-squared distribution with n degrees of freedom: 1. σ. 2 ... The quotient of that sum by σ2 has a chi-squared distribution with only n − 1 degrees of freedom: 1. σ. 2. ∑. i. =. 1. n. r. i ... Mean square error or mean squared error (abbreviated MSE) and root mean square error (RMSE) refer to the amount by which the ... That fact, and the normal and chi-squared distributions given above form the basis of calculations involving the quotient ...
... specifies a chi-squared distribution which describes the associated sum of squares, while the same is true for "treatments" if ... Using the F-distribution is a natural candidate because the test statistic is the ratio of two scaled sums of squares each of ... which follows a scaled chi-squared distribution. The expected value of F is 1. +. n. σ. Treatment. 2. /. σ. Error. 2. {\ ... to the F-distribution with I. −. 1. {\displaystyle I-1}. , n. T. −. I. {\displaystyle n_{T}-I}. degrees of freedom. ...
is the Probability Density Function (PDF) of standard normal distribution. Berkson's minimum chi-square method[edit]. Main ... Then Berkson's minimum chi-square estimator is a generalized least squares estimator in a regression of Φ. −. 1. (. p. ^. t. ) ... Asymptotic distribution for β. ^. {\displaystyle {\hat {\beta }}}. is given by n. (. β. ^. −. β. ). →. d. N. (. 0. ,. Ω. −. 1. ... Minimum chi-square estimation. This method can be applied only when there are many observations of response variable y. i. {\ ...
This result is used to justify using a normal distribution, or a chi square distribution (depending on how the test statistic ... In 1980, White proposed a consistent estimator for the variance-covariance matrix of the asymptotic distribution of the OLS ... While the ordinary least squares estimator is still unbiased in the presence of heteroscedasticity, it is inefficient and ... Gupta, A. K.; Tang, J. (1984). "Distribution of likelihood ratio statistic for testing equality of covariance matrices of ...
... the objective function is a random variable which follows a chi-square distribution, since it is the sum of the square of ... one only has to compare the value of the objective function with the critical value of the chi square distribution. The ... of the probability density function of a chi-square distribution (e.g. the 95th percentile for a 95% confidence) gives an ... The chi square test gives only a rough indication about the existence of gross errors, and it is easy to conduct: ...
Pinheiro and Bates showed in 2000 that the true distribution of this likelihood ratio chi-square statistic could be ... the asymptotic distribution for the test will be χ. 2. (. 1. ). {\displaystyle \chi ^{2}(1)}. , the χ. 2. {\displaystyle \chi ... displaystyle \chi ^{2}(k)}. and χ. 2. (. k. −. 1. ). {\displaystyle \chi ^{2}(k-1)}. . (With k = 1, χ. 2. (. 0. ). {\ ... displaystyle \chi ^{2}(3)}. and χ. 2. (. 4. ). {\displaystyle \chi ^{2}(4)}. was a good match for actual p-values obtained by ...
... an approach based on the chi-square distribution for combining the individual word probabilities into a combined probability ( ... Robinson's method used math-intensive algorithms combined with Chi-square statistical testing to enable computers to examine an ... Fischer's combination of probabilities into a chi-squared distribution, has been extensively tested and is used by the most ... Gary Robinson's Linux Journal article discussed using the chi squared distribution. CS1 maint: discouraged parameter (link) Ben ...
The chi distribution The noncentral chi distribution The chi-squared distribution, which is the sum of the squares of n ... The inverse-chi-squared distribution The noncentral chi-squared distribution The Scaled inverse chi-squared distribution The ... the Cauchy distribution, Holtsmark distribution, Landau distribution, Lévy distribution and normal distribution are special ... The Exponential-logarithmic distribution The F-distribution, which is the distribution of the ratio of two (normalized) chi- ...
The square of a standard normal random variable has a chi-squared distribution with one degree of freedom. If X is a Student's ... Cauchy distribution, Logistic distribution, Error distribution, Power distribution, Rayleigh distribution. Example: If Z is a ... Weibull distribution, logistic distribution, error distribution, power-law distribution, Rayleigh distribution. Example: If X ... The sum of N chi-squared (1) random variables has a chi-squared distribution with N degrees of freedom. Other distributions are ...
... the square root of) a central moment. ... Probability distribution. *Sampling distribution *Order ...
square. 1. The square of a graph G is the graph power G2; in the other direction, G is the square root of G2. The half-square ... χ(G) (using the Greek letter chi) is the chromatic number of G and χ ′(G) is its chromatic index; see chromatic and coloring.. ... 3. Power laws in the degree distributions of scale-free networks are a phenomenon in which the number of vertices of a given ... Square brackets [ ]. G[S] is the induced subgraph of a graph G for vertex subset S.. Prime symbol '. The prime symbol is often ...
If the two distributions are normal with the same mean but different variances, then Pr[ X,Y]=Pr[Y,X] but the size of the Mann- ... Different distributions[edit]. If one is only interested in stochastic ordering of the two populations (i.e., the concordance ... Unlike the t-test it does not require the assumption of normal distributions. It is nearly as efficient as the t-test on normal ... If one desires a simple shift interpretation, the Mann-Whitney U test should not be used when the distributions of the two ...
is the mean square distance of the electrons from the nucleus. Therefore, ⟨. ρ. 2. ⟩. =. ⟨. x. 2. ⟩. +. ⟨. y. 2. ⟩. =. 2. 3. ⟨ ... If the distribution of charge is spherically symmetric, we can suppose that the distribution of x,y,z. coordinates are ... displaystyle \chi =-\mu _{0}{\frac {e^{2}}{12\pi ^{2}m\hbar }}{\sqrt {2mE_{\rm {F}}}},}. where E. F. {\displaystyle E_{\rm {F ... displaystyle \chi ={\frac {\mu _{0}n\mu }{B}}=-{\frac {\mu _{0}e^{2}Zn}{6m}}\langle r^{2}\rangle .}. In atoms, Langevin ...
Square 方茶 方茶 Fāngchá A flat square of tea, usually in 100g or 200g sizes. Characters are often pressed into the square, as in ... Pu'er journals and similar annual guides such as The Profound World of Chi Tse, Pu-erh Yearbook, and Pu-erh Teapot Magazine ... Pu'er tea distribution in Yunnan]. 7yunnan.cn. 2006. Archived from the original on 2006-12-02.. ... For instance, brick or square teas often are not compressed using bags.[14][better source needed] ...
minimizes the weighted least squares-like condition: min. g. ∈. A. ∑. i. =. 1. n. w. i. (. g. (. x. i. ). −. f. (. x. i. ). ). ... Probability distribution. *Sampling distribution *Order statistic. *Empirical distribution *Density estimation. *Statistical ... In terms of numerical analysis, isotonic regression involves finding a weighted least-squares fit x. ∈. R. n. {\displaystyle x\ ...
Student's t distribution, the distribution of the ratio of a standard normal variable and the square root of a scaled chi ... the Bernoulli distribution, the binomial distribution, the geometric distribution, and the negative binomial distribution. ... F-distribution, the distribution of the ratio of two scaled chi squared variables; useful e.g. for inferences that involve ... Chi-squared distribution, the distribution of a sum of squared standard normal variables; useful e.g. for inference regarding ...
... is distributed as part of the larger TeX Live distribution. (Prior to TeX Live, the teTeX distribution was the de facto ... The algorithm will then find the breakpoints that will minimize the sum of squares of the badness (including penalties) of the ... and chi, as TeX is an abbreviation of τέχνη (ΤΕΧΝΗ - technē), Greek for both "art" and "craft", which is also the root word of ... Distributions and extensions[edit]. TeX is usually provided in the form of an easy-to-install bundle of TeX itself along with ...
An estimate of the margin of error in percentage terms can be gained by the formula 100 ÷ square root of sample size ... Probability distribution. *Sampling distribution *Order statistic. *Empirical distribution *Density estimation. *Statistical ...
Ye, S.; Li, Z.; Liu, J;, Zhang, T.; and Xie, S. (2011). "Distribution, Endemism and Conservation Status of Fishes in the ... The basin covers more than 1,245,000 square miles (3,220,000 km2), including all or parts of 32 U.S. states and two Canadian ...
The Wald test can be evaluated against a chi-square distribution.. References[edit]. *^ a b Pearson, Karl (1900). "On the ... Other examples of chi-squared tests[edit]. One test statistic that follows a chi-squared distribution exactly is the test that ... Using the chi-squared distribution to interpret Pearson's chi-squared statistic requires one to assume that the discrete ... Without other qualification, 'chi-squared test' often is used as short for Pearson's chi-squared test. The chi-squared test is ...
... given the probability distribution, the null hypothesis will sometimes be "rejected," that is, deemed not plausible. That is, ... Latin square. *Graeco-Latin square. *Orthogonal array. *Latin hypercube Repeated measures design ...
The B-52 effort was concentrated primarily against suspected Viet Cong targets in South Vietnam, but the Ho Chi Min Trail and ... for property distribution and reuse.[19] ... Sundance Square *Sid Richardson Museum. *Texas Rodeo Cowboy ...
least-squares estimators. ,. S. E. α. ^. ,. S. E. β. ^. =. the standard errors of least-squares estimators. .. {\displaystyle ... Another is Hotelling's T2 statistic follows a T2 distribution. However, in practice the distribution is rarely used, since ... sum of squares of residuals}}.\end{aligned}}}. Then tscore is given by: t. score. =. (. β. ^. −. β. 0. ). n. −. 2. SSR. /. ∑. i ... For non-normal data, the distribution of the sample variance may deviate substantially from a χ2 distribution. However, if the ...
Chi-square test[edit]. When calculating a chi-square test what are the steps between calculating the differences between the ... Call that value X. Then the p-value is just the probability that a χ2 distribution with the appropriate degrees of freedom is ... how is the p-value of the chi-square obtained (other than by looking it up in a table)? Thanks. The chi-square test article ... Least Squares Question[edit]. Let v. 1. =. [. 1. 1. 0. 1. ]. {\displaystyle v_{1}={\begin{bmatrix}1\\1\\0\\1\end{bmatrix}}}. ...
... weighted least squares or asymptotically distribution-free methods. This is often accomplished by using a specialized SEM ... Chi-squared *A fundamental measure of fit used in the calculation of many other fit measures. Conceptually it is a function of ... which indirectly included the two-stage least squares estimator and its asymptotic distribution (Anderson, 2005) and ... Root Mean Square Error of Approximation (RMSEA) *Fit index where a value of zero indicates the best fit.[15] While the ...
Page with Chi Rho monogram from the Gospel of Matthew in the Lindisfarne Gospels c. 700, possibly created by Eadfrith of ... Various studies have been carried out investigating the distribution and chronological change of bead types.[232][233] The ... One style flourished from the late 5th century, and continued throughout the 6th, and is on many square-headed brooches, it is ... Buildings vary widely in size, most were square or rectangular, though some round houses have been found. Frequently these ...
... frequentist statistics studies the sampling distribution while Bayesian statistics updates a probability distribution on the ... Latin square. *Graeco-Latin square. *Orthogonal array. *Latin hypercube. Repeated measures design ... The average error is zero; the standard deviations of the probability distribution of the errors is the same number σ on ...
... is complementary to the chi square test, which takes into account the distances but not the signs. The Kolmogorov-Smirnov test ... Runs tests can be used to test: the randomness of a distribution, by taking the data in the given order and marking with + the ... However, the reverse is true if the distributions differ in variance and have at the most only a small difference in location.[ ... Under the null hypothesis, the number of runs in a sequence of N elements is a random variable whose conditional distribution ...
Latin square. *Graeco-Latin square. *Orthogonal array. *Latin hypercube Repeated measures design ... Probability distribution. *Sampling distribution *Order statistic. *Empirical distribution *Density estimation. *Statistical ...
The Shanghai Ghetto, formally known as the Restricted Sector for Stateless Refugees, was an area of approximately one square ... "Refuge in Shanghai (1938-1953)" American Jewish Joint Distribution Committee Archives. *Jewish Voice of the Far East = ... Wu2 kuo2-chi2 nan4-min2 hsien4-ting4 ti4-ch'ü1. ... The Baghdadis and later the American Jewish Joint Distribution ... In 1943, the occupying Japanese army required these 18,000 Jews to relocate to a 3/4 square mile area of Shanghai's Hongkou ...
In 2008 the Final Fantasy developer Square Enix announced that it was partnering with NeuroSky to create a game, Judecca.[115][ ... both sides, symmetrical distribution, most evident frontally; low-amplitude waves. *range span: active calm → intense → ... Wan, Feng; da Cruz, Janir Nuno; Nan, Wenya; Wong, Chi Man; Vai, Mang I; Rosa, Agostinho (2016-05-06). "Alpha neurofeedback ... It can be seen as a focal disturbance in focal subcortical lesions; it can be seen in generalized distribution in diffuse ...
... specifies a chi-squared distribution which describes the associated sum of squares, while the same is true for "treatments" if ... to the F-distribution with I. −. 1. {\displaystyle I-1}. , n. T. −. I. {\displaystyle n_{T}-I}. degrees of freedom. Using the F ... because the test statistic is the ratio of two scaled sums of squares each of which follows a scaled chi-squared distribution. ... where MS is mean square, I. {\displaystyle I}. = number of treatments and n. T. {\displaystyle n_{T}}. = total number of cases ...
Widely used pivots include the z-score, the chi square statistic and Student's t-value. ... the method of moments for the fitting of distributions to samples and the Pearson distribution, among many other things.[22] ... Least squares applied to linear regression is called ordinary least squares method and least squares applied to nonlinear ... Many statistical methods seek to minimize the residual sum of squares, and these are called "methods of least squares" in ...
Kwong, Chi Man (9 September 2015). "Hong Kong during World War II: A Transnational Battlefield". University of Nottingham. ... With over 7.4 million people of various nationalities[d] in a 1,104-square-kilometre (426 sq mi) territory, Hong Kong is one of ... Thematic Report: Household Income Distribution in Hong Kong (PDF). 2016 Population By-Census (Report). Census and Statistics ... Tam, Maria Wai-chu; Chan, Eugene Kin-keung; Choi Kwan, Janice Wing-kum; Leung, Gloria Chi-kin; Lo, Alexandra Dak-wai; Tang, ...
The Euclidean metric (Principal Component Analysis), the Chi-Square distance (Correspondence Analysis) or the Generalized ... Spatial distribution: the similar spatial object groups positioning information, including distribution, trends, contrast etc.. ... Scheldeman, X. & van Zonneveld, M. (2010). Training Manual on Spatial Analysis of Plant Diversity and Distribution. Bioversity ... Spread of bubonic plague in medieval Europe.[citation needed] The colors indicate the spatial distribution of plague outbreaks ...
The forms for visa application many Western countries use, has a square for writing the last name which cannot be left unfilled ... Ho Chi Minh) and Japanese names do (Kenzaburō Ōe).[11] However, numerous exceptions exist, particularly for people born in ... the systematic distribution of surnames to Filipinos without prior surnames and the universal implementation of the Spanish ...
Probability distribution. *Sampling distribution *Order statistic. *Empirical distribution *Density estimation. *Statistical ...
... then it is asymptotically unbiased and it converges in distribution to the normal distribution: n. (. δ. n. −. θ. 0. ). →. N. ( ... Minimum mean square error estimation[edit]. Main article: Minimum mean square error ... The prior distribution p. {\displaystyle p}. has thus far been assumed to be a true probability distribution, in that ... is known to have a prior distribution π. {\displaystyle \pi }. . Let θ. ^. =. θ. ^. (. x. ). {\displaystyle {\widehat {\theta ...
"Household Income Distribution, 1967 to 2005" (PDF). U.S. Census Bureau. 2006. Diakses tanggal 2006-12-28. ... Tiananmen Square protests · Singing Revolution · Fall of the Berlin Wall · Revolutions of 1989 ...
In this paper, a simple chi-square approximation for the cumulative distribution of the F-distribution is obtained via an ... For example, it is used for testing: equality of variances of two independent normal distributions, equality of means in the ... This new approximation exhibits remarkable accuracy even when the degrees of freedom of the F distribution are small. ... F distribution is one of the most frequently used distributions in statistics. ...
Students compare the chi-square distribution to the standard normal distribution and determine how the Chi-Square distribution ... Students compare the chi-square distribution to the standard normal distribution and determine how the Chi-Square distribution ... Problem 2 gives students the opportunity to explore the critical values for a Chi-Square Distribution. They find the critical ... In Problem 1, students will explore the characteristics of the Chi-Square Distribution. They will increase the degree of ...
Table 5 Chi-Square Probability Distribution Selected right-tail areas - Selection from The Complete Idiots Guide to Statistics ... Chi-Square Probability Distribution Table 5 provides the chi-square for the corresponding value of alpha and the number of ... Chi-Square Probability Distribution. Table 5 provides the chi-square for the corresponding value of alpha and the number of ...
A Powerful Variant-Set Association Test Based on Chi-Square Distribution Message Subject (Your Name) has forwarded a page to ... A Powerful Variant-Set Association Test Based on Chi-Square Distribution. Zhongxue Chen, Tong Lin and Kai Wang ... A Powerful Variant-Set Association Test Based on Chi-Square Distribution. Zhongxue Chen, Tong Lin and Kai Wang ... A Powerful Variant-Set Association Test Based on Chi-Square Distribution. Zhongxue Chen, Tong Lin and Kai Wang ...
We derive Laguerre expansions for the density and distribution functions of a sum of positive weighted noncentral chi-square ... Ashour, S. K. andAbdel-Samad, A. I. (1990). On the computation of noncentral chi-square distribution function.Communications in ... Gideon, R. A. andGurland, J. (1977). Some alternative expansions for the distribution function of a noncentral chi-square ... We derive Laguerre expansions for the density and distribution functions of a sum of positive weighted noncentral chi-square ...
Chi-square distribution a distribution in which a variable is distributed like the sum of the the squares of any given ... The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of ... Retrieved from "https://www.biology-online.org/dictionary/index.php?title=Chi-square_distribution&oldid=57790" ... independent random variable, each of which has a normal distribution with mean of zero and variance of one. ...
What is Chi-square distribution? Meaning of Chi-square distribution as a legal term. What does Chi-square distribution mean in ... Definition of Chi-square distribution in the Legal Dictionary - by Free online English dictionary and encyclopedia. ... Chi-square distribution legal definition of Chi-square distribution https://legal-dictionary.thefreedictionary.com/Chi-square+ ... 1] has a noncentral chi-square distribution then the distribution of X = [square root of [X. ...
Distribution for random variables constrained to be equal to or greater than 0 and which (unlike normal distribution) traces an ... Distribution for random variables constrained to be equal to or greater than 0 and which (unlike normal distribution) traces an ...
Chi-Square Distribution Female Glucose Tolerance Test Humans Incidence Male Middle Aged Multivariate Analysis Myocardial ... Chi-Square Distribution Cross-Sectional Studies Female Humans Linear Models Longitudinal Studies Middle Aged Mouth, Edentulous ... Chi-Square Distribution Confounding Factors (Epidemiology) Finland Humans Longitudinal Studies Male Manuals as Topic Middle ... Chi-Square Distribution Cohort Studies Female Finland Follow-Up Studies Humans Male Mandibular Condyle - physiopathology - ...
F and Chi square distributions. Click the image or link below for tables of critical test values for different distributions. ...
Actually, when the null hypothesis is not trivially violated, the noncentral chi-square distribution cannot describe the LR ... noncentral chi-square distribution is commonly used to describe the behavior of the likelihood ratio (LR) statistic under ... it is widely believed that the noncentral chi-square distribution is justified by statistical theory. ... Due to the inaccessibility of the rather technical literature for the distribution of the LR statistic, ...
... distribution from CHEM 115L at Grand Canyon. Chi square test 2-The student population at the state college consists of 55% ... Chi-square+Test-Gender+distribution - Chi square test 2-The.... This preview shows document pages 1 - 2. Sign up to view the ... Chi square test 2-The student population at the state college consists of 55% female and 45% males. a- The college theater ... Is the gender distribution for theater goers significantly different from the distribution for the general college? Test at the ...
Can we use chi-square distribution and central limit theorem to find the approximate normal distribution? ... Okay, so I am interested if there is a way to derive the variance for a Chi-Square distribution using the property that it is ... Note: I can solve this using integration of the PDF for the Chi-Square distribution, but I was wondering if there is any way to ... Variance of Chi Square Distribution as the Sum of Unit Normal Random Variables. Ask Question ...
Generalized chi-square distribution Hotellings T-square distribution Noncentral chi-square distribution Pearsons chi-square ... square distribution Noncentral t-distribution can be obtained from normal distribution and chi-square distribution A chi-square ... of chi-square distribution Students t-distribution can be obtained from chi-square distribution and normal distribution ... Inverse-chi-square distribution) The chi-square distribution is a special case of type III Pearson distribution If X ∼ χ 2 ( ν ...
Free Statistics Calculators: Home , Related Calculators: Probability Density Function (PDF) for the Chi-Square Distribution ... Probability Density Function (PDF) for the Chi-Square Distribution Related Calculators. Below you will find descriptions and ... calculator for the chi-square distribution. The related calculators have been organized into categories in order to make your ... Probability Density Function (PDF) Calculator for the F-Distribution * Probability Density Function (PDF) Calculator for the ...
Tags chi sq test chi square chi square help what test distribution dot product six sigma weighted average ... I think I need to steer towards some sort of Chi-Square Distribution. I also think I need some bounding built in to take care ... Should I use some sort of Chi Square Distribution or another method... Any assistance is greatly appreciated.. ...
Chi-square distribution come together and discuss about Chi-square distribution. Please use the message board below to post ... F-distribution Forum. • Chi distribution Forum. • Exponential distribution Forum. • Erlang distribution Forum. • Linear ... Standard normal distribution Forum. • Iid Forum. • Noncentral chi-square distribution Forum. • Idempotent matrix Forum. • Rank ... There are no entries in Chi-square distribution forum. Become the first person to post messages in this forum by using the form ...
Class: Chi-square distribution. http://cll.niimm.ksu.ru/ontologies/mathematics#E2533. Annotations (3). * comment "В.С. ...
CHI-SQUARE DISTRIBUTION FUNCTION - Selection from Introduction to Probability and Stochastic Processes with Applications [Book] ... APPENDIX D STATISTICAL TABLES D.1 BINOMIAL PROBABILITIES D.2 POISSON PROBABILITIES D.3 STANDARD NORMAL DISTRIBUTION FUNCTION D. ... D.3 STANDARD NORMAL DISTRIBUTION FUNCTION. D.4 CHI-SQUARE DISTRIBUTION FUNCTION. ...
Chi Square distribution[edit]. Quantile of the Chi-square distribution (. χ. 2. {\displaystyle \chi ^{2}}. distribution) ... Discrete distributions[edit]. Benford Distribution[edit]. The Benford distribution is the distribution of the first digit of a ... Extreme values and related distribution[edit]. *The Gumbel distribution. *The logistic distribution : distribution of the ... Uniform distribution[edit]. We can sample n. values from a uniform distribution (also known as a rectangular distribution] ...
Chi-square distribution The chi-square distribution has one parameter k, the degrees of freedom. The chi squared distribution ... Chi square. chi square test, chi square distribution, expected frequency, observed frequency. contingency table, significance ... Chi-square test explained. Chi-square test is based on the chi square distribution. It is used for the goodness-of-fit test ... chi square is greater than the critical value of chi square that cuts off the upper 5% of the distribution at our particular ...
Upper limit of integration of the non-central chi-square distribution. Input range: [0, +infinity). Search range: [0,1E300] ... Degrees of freedom of the non-central chi-square distribution. Input range: (0, +infinity). Search range: [ 1E-300, 1E300] ... The integral from 0 to X of the non-central chi-square distribution. Input range: [0, 1-1E-16). ... Non-centrality parameter of the non-central chi-square distribution. Input range: [0, +infinity). Search range: [0,1E4] ...
3 thoughts on "Chi Square Probability Distribution Code Using PHP" * annotated October 16, 2013. "…In order to use this ... distribution based on input data. In order to use this function the researcher must calculate the value first by using the ...
Chi-Square Distribution. The chi-square distribution is a univariate distribution which results when univariate-normal ... chi-square distribution *Wishart distribution Normal Distribution. The normal, or Gaussian, distribution is one of the most ... These chi-square distributions are themselves additive. That is, a chi-square-distributed variable with d1 degrees of freedom ... the chi-square distribution is skewed to the right, and has a minimum of 0. The degrees of freedom of the resulting chi-square ...
... for the parameters of a normal distribution, using the sample data in the vector data. ... Add a scale parameter to the chi-square distribution for adapting to the scale of data and fit it. First, generate sample data ... Estimate the parameters of the noncentral chi-square distribution from the sample data. To do this, custom define the ... Generate sample data of size 1000 from a noncentral chi-square distribution with degrees of freedom 8 and noncentrality ...
6634-The chi-square distribution becomes more symmetrical as A. degrees of freedom increase B. degrees... ...
Test Statistic in Chi-Square Test (Replies: 1) * Pearsons chi-square test versus chi-squared distribution (Replies: 4) ... Similar Discussions: Pearson chi-squared test (χ2): differences? * Chi-Squared Test (Replies: 1) ... Does the sample represent the theoretical distribution?. So, you would use a test for fit of distribution, but how much of a ... So, as far as I know, there are two χ2-tests: test for fit of a distribution & Test of independence. How big of a mistake ...
To understand probability distributions, it is important to understand variables. random variables, and some notation. A ... Download ppt "Presentation on Probability Distribution * Binomial * Chi-square" * Ppt on journal ledger and trial balance ... Presentation on Probability Distribution * Binomial * Chi-square. Published byAriana Lidstone Modified over 2 years ago ... 1 Presentation on Probability Distribution * Binomial * Chi-square. Presenters: Nouruddin Boojhawoonah & Poonam Gopaul Notes ...
The Chi-Square Distribution * The Chi-Square Test * Fishers Exact Test * McNemars Test for Matched Pairs ...
Noncentral chi-squared distribution. From Wikipedia, the free encyclopedia. (Redirected from Noncentral chi-square distribution ... Various chi and chi-squared distributions Name. Statistic chi-squared distribution. ∑. 1. k. (. X. i. −. μ. i. σ. i. ). 2. {\ ... displaystyle \chi ^{2}}. distribution is a generalization of the chi-squared distribution. This distribution often arises in ... Related distributions[edit]. *If V. {\displaystyle V}. is chi-squared distributed V. ∼. χ. k. 2. {\displaystyle V\sim \chi _{k ...
  • For these hypothesis tests, as the sample size, n, increases, the sampling distribution of the test statistic approaches the normal distribution (central limit theorem). (wikipedia.org)
  • The normal, or Gaussian, distribution is one of the most familiar in statistics, endeared to statisticians by its simplicity and by virtue of the Central Limit Theorem (which states that a sample mean will follow an approximately normal distribution, if sample size is large enough, even if the data themselves are not normally distributed). (gsu.edu)
  • The negative binomial distribution is the distribution of the number of failures before k successes in a series of Bernoulli events. (wikibooks.org)
  • This applet demonstrates the Binomial distribution by simulating Galton's Board, dropping balls through a triangular array of nails. (causeweb.org)
  • function uses the binomial distribution. (delorie.com)
  • Many other statistical tests also use this distribution, such as Friedman's analysis of variance by ranks. (wikipedia.org)
  • The chi-square distribution is used primarily in hypothesis testing, and to a lesser extent for confidence intervals for population variance when the underlying distribution is normal. (wikipedia.org)
  • Another example is the test statistic for testing equality of means of k independent normal distributions with homogeneous variance is also distributed as an F distribution. (scirp.org)
  • In this paper, we consider the problem of testing equality of means of k independent normal distributions with homogeneous variance. (scirp.org)
  • a distribution in which a variable is distributed like the sum of the the squares of any given independent random variable , each of which has a normal distribution with mean of zero and variance of one. (biology-online.org)
  • Xv*Xv is Chi-square distributed with v degrees of freedom with mean = v and variance = 2*v . The importance of the Chi-square distribution stems from the fact that it describes the distribution of the Variance of a sample taken from a Normal distributed population. (uva.nl)
  • The distribution of the underlying sample values X has mean = 0 and variance = 1 , i.e., is Standard Normal . (uva.nl)
  • Okay, so I am interested if there is a way to derive the variance for a Chi-Square distribution using the property that it is the sum of independent unit normal distributions squared. (stackexchange.com)
  • distribution is obtained from the values of the ratio of the sample variance and population variance multiplied by the degrees of freedom. (richland.edu)
  • The mean and variance of the chi square distribution also increase as k increases and the mean = k and variance = 2 k . (symynet.com)
  • The normal distribution has two parameters, one representing the mean of the variable and one representing the variance. (gsu.edu)
  • The standard normal distribution, which constrains the mean to 0 and the variance to 1, is probably the most widely known statistical distribution. (gsu.edu)
  • The mean of a chi-square distribution is equal to its degrees of freedom, and the variance is equal to twice the degrees of freedom. (gsu.edu)
  • Understand the role and use of moment generating functions and be able to use them to compute the expectation and variance of standard distributions. (york.ac.uk)
  • In probability theory and statistics, the chi-square distribution (also chi-squared or χ2-distribution) with k degrees of freedom is the distribution of a sum of the squares of k independent standard normal random variables. (wikipedia.org)
  • Zk are independent, standard normal random variables, then the sum of their squares, Q = ∑ i = 1 k Z i 2 , {\displaystyle Q\ =\sum _{i=1}^{k}Z_{i}^{2},} is distributed according to the chi-square distribution with k degrees of freedom. (wikipedia.org)
  • The chi-square distribution has one parameter: a positive integer k that specifies the number of degrees of freedom (the number of random variables being summed, Zi s). (wikipedia.org)
  • This new approximation exhibits remarkable accuracy even when the degrees of freedom of the F distribution are small. (scirp.org)
  • distribution, where r is the degrees of freedom, which is the difference in the number of unconstrained parameters being estimated and the number of constrained parameters being estimated. (scirp.org)
  • Students compare the chi-square distribution to the standard normal distribution and determine how the Chi-Square distribution changes as they increase the degrees of freedom. (ti.com)
  • As the degrees of freedom increase the distribution becomes less skewed and more symmetric. (ti.com)
  • Table 5 provides the chi-square for the corresponding value of alpha and the number of degrees of freedom. (oreilly.com)
  • The chi-square distribution has one parameter k , the degrees of freedom. (symynet.com)
  • If we wish to reject H o at the .05 level, we will determine if our value of chi square is greater than the critical value of chi square that cuts off the upper 5% of the distribution at our particular degrees of freedom value. (symynet.com)
  • Degrees of freedom of the non-central chi-square distribution. (scilab.org)
  • The degrees of freedom of the resulting chi-square distribution are equal to the number of variables that are summed. (gsu.edu)
  • That is, a chi-square-distributed variable with d1 degrees of freedom can be added to one with d2 degrees of freedom to yield a chi-square-distributed variable with d1 + d2 degrees of freedom, as long as the two added variables are independent. (gsu.edu)
  • Generate sample data of size 1000 from a noncentral chi-square distribution with degrees of freedom 8 and noncentrality parameter 3. (mathworks.com)
  • Explain how the degrees of freedom affect a Chi-Square Distribution. (foxessays.com)
  • and the conditional distribution of Z given J = i is chi-squared with k + 2 i degrees of freedom. (wikipedia.org)
  • Chi square distribution explains a variable with k degrees of liberty, dispersed like the amount of the squares of n independent random variables each which have a typical distribution with mean of absolutely no and variation of 1. (academicpaperwriter.com)
  • You can quickly depend on our Chi-Square Distributions composing Help as we offer the very best services and these services are supplied to the students by our professionals who all hold master and specialized degrees or more. (academicpaperwriter.com)
  • Visualize how changes in degrees of freedom affect the shape of the chi square distribution. (rdrr.io)
  • We can use a chi square test with 12-1=11 degrees of freedom to compare the observed data against our null hypothesis. (ucla.edu)
  • Using the SOCR Chi-Square Distribution Calculator, at 11 degrees of freedom, a chi square value of 8.8 gives us a p-value of 0.36. (ucla.edu)
  • f_{Y_{k+2i}}(x),} where Y q {\displaystyle Y_{q}} is distributed as chi-square with q {\displaystyle q} degrees of freedom. (wikipedia.org)
  • Suppose that a random variable J has a Poisson distribution with mean λ / 2 {\displaystyle \lambda /2} , and the conditional distribution of Z given J = i is chi-square with k + 2i degrees of freedom. (wikipedia.org)
  • Siegel (1979) discusses the case k = 0 specifically (zero degrees of freedom), in which case the distribution has a discrete component at zero. (wikipedia.org)
  • Dear Li, if you're interested in the values rather than in doing a programming exercise, you can use the statistics2 package by Shin-ichi Hara: blade.nagaokaut.ac.jp/~sinara/ruby/math/statistics2/statistics2-0.50/README From the README: --- Statistics2.chi2dist(n, x) Returns the integral of Chi-squared distribution with n degrees of freedom over (-Infty, x]. (ruby-forum.com)
  • Statistics2.chi2X_(n, x) Returns the integral of Chi-squared distribution with n degrees of freedom over [0, x]. (ruby-forum.com)
  • For this reason, it is preferable to use the t distribution rather than the normal approximation or the chi-square approximation for a small sample size. (wikipedia.org)
  • In this paper, a simple chi-square approximation for the cumulative distribution of the F -distribution is obtained via an adjusted log-likelihood ratio statistic. (scirp.org)
  • As a result, a normal approximation for the cdf of the F distribution is obtained. (scirp.org)
  • approximation for the cdf of the F distribution is obtained. (scirp.org)
  • A gaussian approximation to the distribution of a definite quadratic form. (springer.com)
  • Note on an approximation to the distribution of non-central χ 2 . (springer.com)
  • This applet demonstrates the Normal approximation to the Poisson Distribution. (causeweb.org)
  • The basis for his statistical mathematics came from a long tradition of work on the method of least squares approximation , worked out early in the 19th century in order to estimate quantities from repeated astronomical and geodetic measures using probability theory . (britannica.com)
  • The proposed low complexity technique is analyzed in an oversampled OFDM system and a simple distribution approximation of the oversampled and linearly filtered OFDM signals is also proposed. (scirp.org)
  • Below you will find descriptions and links to 10 different statistics calculators that are related to the free probability density function (pdf) calculator for the chi-square distribution. (danielsoper.com)
  • Discrete distributions are defined by their probability function rather than by their probability density function in order to avoid singularities. (maplesoft.com)
  • Formula 26.4.25 of Abramowitz and Stegun, Handbook of Mathematical Functions (1966) is used to compute the cumulative distribution function. (scilab.org)
  • The functions in this section compute various probability distributions. (delorie.com)
  • Compute the 99% confidence interval for the distribution parameters. (mathworks.com)
  • absolutely continuous distributions. (mcgill.ca)
  • Surveys basic statistical methods used in the genetics and epidemiology literature, including maximum likelihood and least squares. (wiley.com)
  • Be able to estimate parameters of standard distributions following the Maximum Likelihood approach. (york.ac.uk)
  • Continuous univariate distributions , vol. 2 of Wiley Series in Probability and Mathematical Statistics: Applied Probability and Statistics . (springer.com)
  • This page provides a table of Chi-square distribution probabilities with degress of freedom 1-45. (causeweb.org)
  • This page provides a table of F distribution probabilities for alpha = 0.10, 0.05, 0.025, and 0.01. (causeweb.org)
  • these two values and two probabilities make up the probability distribution of the single coin flipping event. (mcgill.ca)
  • This distribution is sometimes called the central chi-square distribution, a special case of the more general noncentral chi-square distribution. (wikipedia.org)
  • We derive Laguerre expansions for the density and distribution functions of a sum of positive weighted noncentral chi-square variables. (springer.com)
  • On the computation of noncentral chi-square distribution function. (springer.com)
  • Some alternative expansions for the distribution function of a noncentral chi-square random variable. (springer.com)
  • 1] has a noncentral chi-square distribution then the distribution of X = [square root of [X. (thefreedictionary.com)
  • In the literature of mean and covariance structure analysis, noncentral chi-square distribution is commonly used to describe the behavior of the likelihood ratio (LR) statistic under alternative hypothesis. (ed.gov)
  • Due to the inaccessibility of the rather technical literature for the distribution of the LR statistic, it is widely believed that the noncentral chi-square distribution is justified by statistical theory. (ed.gov)
  • Actually, when the null hypothesis is not trivially violated, the noncentral chi-square distribution cannot describe the LR statistic well even when data are normally distributed and the sample size is large. (ed.gov)
  • Examples with real data illustrate the difference between the noncentral chi-square distribution and the normal distribution. (ed.gov)
  • Monte Carlo results compare the strength of the normal distribution against that of the noncentral chi-square distribution. (ed.gov)
  • The aim is to provide the least technical material for quantitative graduate students in social science to understand the condition and limitation of the noncentral chi-square distribution. (ed.gov)
  • Estimate the parameters of the noncentral chi-square distribution from the sample data. (mathworks.com)
  • In probability theory and statistics, the noncentral chi-square distribution (or noncentral chi-squared distribution, noncentral χ 2 {\displaystyle \chi ^{2}} distribution) is a noncentral generalization of the chi-square distribution. (wikipedia.org)
  • Then the random variable ∑ i = 1 k X i 2 {\displaystyle \sum _{i=1}^{k}X_{i}^{2}} is distributed according to the noncentral chi-square distribution. (wikipedia.org)
  • From this representation, the noncentral chi-square distribution is seen to be a Poisson-weighted mixture of central chi-square distributions. (wikipedia.org)
  • The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution . (biology-online.org)
  • Much of the distributional theory that underlies SEM today is built upon a handful of continuous statistical distributions--some well known, and some less so. (gsu.edu)
  • Any good advanced statistical text can provide details on the distributions discussed here. (gsu.edu)
  • The normal distribution also lies at the root of many other continuous statistical distributions. (gsu.edu)
  • On the good side, statistical derivations involving the normal distribution are very much simplified, since higher order moments can be ignored. (gsu.edu)
  • On the bad side, normal distributions increase the likelihood that the parameters of statistical models will not be identified , because there will be relatively few pieces of distinct information--fewer "knowns"--available for this purpose ( Bekker, Merckens and Wansbeek, 1994 ). (gsu.edu)
  • A probability distribution is a table or an equation that links each outcome of a statistical experiment with its probability of occurence. (slideplayer.com)
  • A Chi-square test is a statistical hypothesis test where tasting distribution of the test data is specified as a chi square distribution while either the null hypothesis holds true or it is asymptotically real. (academicpaperwriter.com)
  • Monte Carlo and Statistical Distributions. (routledge.com)
  • Probability and Statistical Inference 1 (Autumn) will give students a theoretical and mathematically formal framework for joint and conditional distributions of random variables and for studying the asymptotic behaviour of sequences of random variables. (york.ac.uk)
  • function uses the F distribution, used in various statistical tests. (delorie.com)
  • In between there are full chapters on parametric probability distributions, sampling, Chi-Square distributions, point estimation, and tests of parametric statistical hypotheses. (maa.org)
  • From DCDFLIB: Library of Fortran Routines for Cumulative Distribution Functions, Inverses, and Other Parameters (February, 1994) Barry W. Brown, James Lovato and Kathy Russell. (scilab.org)
  • Be able to derive a confidence interval, exact and/or approximate, for parameters of probability distributions. (york.ac.uk)
  • Understand the theoretical framework of linear regression models: standard model assumptions, Least Squares estimators for the model parameters and their properties, inference techniques for the model parameters. (york.ac.uk)
  • The arguments to the algebraic functions are the value of the random variable first, then whatever other parameters define the distribution. (delorie.com)
  • The intervals next to the parameter estimates are the 95% confidence intervals for the distribution parameters. (mathworks.com)
  • Returns the cumulative distribution function, its inverse, or one of its parameters, of the beta distribution. (php.net)
  • Johnson and Kotz [1] give a comprehensive review on the approximations to the cumulative distribution function (cdf) of the F distribution. (scirp.org)
  • Define a custom probability density and cumulative distribution function. (mathworks.com)
  • A probability distribution is called discrete if its cumulative distribution function only increases in jumps. (mcgill.ca)
  • Bentler's EQS package includes estimators specifically designed to be appropriate for elliptical distributions. (gsu.edu)
  • Unbiased estimators of multivariate discrete distributions and chi-square goodness-of-fit test. (eudml.org)
  • BAN estimator}, language = {eng}, number = {3}, pages = {301-326}, title = {Unbiased estimators of multivariate discrete distributions and chi-square goodness-of-fit test. (eudml.org)
  • For example, it is used for testing: equality of variances of two independent normal distributions, equality of means in the one-way ANOVA setting, overall significance of a normal linear regression model, and so on. (scirp.org)
  • For example, the test statistic for testing equality of variances of two independently distributed normal distributions is distributed as an F distribution. (scirp.org)
  • On the other hand, considering testing equality of variances of two independent normal distributions, Wong [3] derives the modified signed log-likelihood ratio statistic. (scirp.org)
  • In classical statistics, there are three distributions often used in hypothesis testing: F and Chi-square distributions used in comparing variances and t distributions in comparing means. (thefreedictionary.com)
  • Conducting a Chi-Square Goodness of the Fit Test revealed that the class of 200 students does not fit the historical pattern when using a .05 significance level. (cram.com)
  • Chi-Square Distributions has fantastic significance in stats. (academicpaperwriter.com)
  • At the .05 significance level is there a difference in the two distributions? (scribd.com)
  • Chi-square is non-symmetric. (richland.edu)
  • Since the chi-square distribution isn't symmetric, the method for looking up left-tail values is different from the method for looking up right tail values. (richland.edu)
  • The chi squared distribution becomes more symmetric as k increases. (symynet.com)
  • The distribution is unimodal and symmetric about the mean. (gsu.edu)
  • Elliptical distributions are symmetric and unimodal, but are not constrained regarding kurtosis. (gsu.edu)
  • While the normal distribution is symmetric, the chi-square distribution is skewed to the right, and has a minimum of 0. (gsu.edu)
  • A symmetric distribution, such as normal distribution, might not be a good fit. (mathworks.com)
  • Because the test statistic (such as t) is asymptotically normally distributed, provided the sample size is sufficiently large, the distribution used for hypothesis testing may be approximated by a normal distribution. (wikipedia.org)
  • Thus, as the sample size for a hypothesis test increases, the distribution of the test statistic approaches a normal distribution. (wikipedia.org)
  • is based on the asymptotic distribution of the log-likelihood ratio statistic. (scirp.org)
  • Using the one-dimensional case, this article provides the details showing that the LR statistic asymptotically follows a normal distribution, which also leads to an asymptotically correct confidence interval for the discrepancy between the null hypothesis/model and the population. (ed.gov)
  • Chi-square Test Statistic. (routledge.com)
  • the Chi-square test statistic, your sample statistic. (coursera.org)
  • The chi-square distribution is a special case of the gamma distribution and is one of the most widely used probability distributions in inferential statistics, notably in hypothesis testing and in construction of confidence intervals. (wikipedia.org)
  • The chi-square distribution is used in the common chi-square tests for goodness of fit of an observed distribution to a theoretical one, the independence of two criteria of classification of qualitative data, and in confidence interval estimation for a population standard deviation of a normal distribution from a sample standard deviation. (wikipedia.org)
  • Thus, elliptical distributions themselves can be thought of as an intermediate point between the normal distribution and the general continuous distribution described in Browne's (1982) work on asymptotically distribution-free (ADF) estimation. (gsu.edu)
  • Using the general theory of estimation and the results of Patil (1965) and Patel (1978) we give the tables of MVUE's for functions of parameter θ of trinomial, multinomial, negative-multinomial and left-truncated modified power series distributions. (eudml.org)
  • We have applied the properties of MVUE's and the results from the theory of MVU estimation to construct a goodness-of-fit chi-squared test for multivariate modified power series distributions. (eudml.org)
  • It is also used in confidence interval estimation for a population standard deviation of a normal distribution from a sample standard deviation. (ucla.edu)
  • The Poisson distribution is shown in blue, and the Normal distribution is shown in red. (causeweb.org)
  • Unlike more widely known distributions such as the normal distribution and the exponential distribution, the chi-square distribution is not as often applied in the direct modeling of natural phenomena. (wikipedia.org)
  • recency effects * halo effects * primacy effects * leniency effects For a chi-square test involving a contingency table, suppose the null hypothesis is rejected. (cram.com)
  • Simply puts chi-square test is a test with test fact that has a chi-square distribution when the null hypothesis holds true, or any where the likelihood distribution of the test figure (presuming the null hypothesis holds true) can be made to approximate a chi-square distribution as carefully as preferred by making the sample size huge enough. (academicpaperwriter.com)
  • If there is substantial distinction from the null hypothesis or weather the outcomes support the null hypothesis, Chi square table is made use of in Chi square test to examine. (academicpaperwriter.com)
  • In our example, the p-values based on the nominal chi-square distribution were often similar to those based on the Monte Carlo simulations. (thefreedictionary.com)
  • The resulting noncentral distributions are characterized by one additional parameter--a noncentrality parameter. (gsu.edu)
  • The Chi-Square distribution is used in the chi-square tests for goodness of fit of an observed distribution to a theoretical one and the independence of two criteria of classification of qualitative data. (ucla.edu)
  • F distribution is one of the most frequently used distributions in statistics. (scirp.org)
  • Information about and tables for the chi-square distribution can be found in any elementary statistics text. (thefreedictionary.com)
  • Browse other questions tagged probability statistics probability-distributions random-variables covariance or ask your own question . (stackexchange.com)
  • Chi- Square Goodness of Fit Testing Assuming Equal Expected A handful of students loves numbers and selects a major in Finance, Statistics, or Marketing. (cram.com)
  • Presenters: Nouruddin Boojhawoonah & Poonam Gopaul Notes reffered from statistics tutorial: Probability distribution. (slideplayer.com)
  • This distribution arises in multivariate statistics as a derivative of the multivariate normal distribution . (wikipedia.org)
  • This help page describes the probability distributions provided in the Statistics package, how to construct random variables using these distributions and the functions that are typically used in conjunction with these distributions. (maplesoft.com)
  • The concept of the probability distribution and the random variables which they describe underlies the mathematical discipline of probability theory , and the science of statistics . (mcgill.ca)
  • Chi Square Test for Goodness of Fit: There are 60 people in a statistics class, and we have data on the month of their birth. (ucla.edu)
  • The geometric distribution . (wikibooks.org)
  • Random variate generator for the geometric distribution, computing the number of failures before success. (haskell.org)
  • Random variate generator for geometric distribution for number of trials. (haskell.org)
  • If we're given a sample mean, sample standard deviation,…sample size, and alpha,…what we can do is use the sampling distribution of the mean…to find the one minus alpha confidence interval. (lynda.com)
  • The standard error of the mean equals…the sample standard deviation divided by…the square root of the sample size,…which is 30 divided by the square root of 100,…or 30 divided by 10, which is three. (lynda.com)
  • The distribution of homogeneous and non-homogeneous quadratic functions of normal variables. (springer.com)
  • The Chi-Square Goodness of Fit Test are calculations done on categorical data. (cram.com)
  • The primary reason for which the chi-square distribution is extensively used in hypothesis testing is its relationship to the normal distribution. (wikipedia.org)
  • Propability density function ( chi-square distribution). (blogspot.com)
  • So, we construct a contingency table that shows the distribution of one variable at each level of the other variable. (symynet.com)
  • Testing hypotheses using a normal distribution is well understood and relatively easy. (wikipedia.org)
  • Note that some references define λ {\displaystyle \lambda } in other ways, such as half of the above sum, or its square root. (wikipedia.org)
  • While the central chi-square distribution is the squared norm of a random vector with N ( 0 k , I k ) {\displaystyle N(0_{k},I_{k})} distribution (i.e., the squared distance from the origin to a point taken at random from that distribution), the non-central χ 2 {\displaystyle \chi ^{2}} is the squared norm of a random vector with N ( μ , I k ) {\displaystyle N(\mu ,I_{k})} distribution. (wikipedia.org)
  • If you do not have the sufficient time or be it any issue in concerns to your Chi-Square Distributions paper, we would be right here to assist you 24/7 with our extremely certified panel of online Chi-Square Distributions tutors who have several years of market experience assisting students with their Chi-Square Distributions composing aid. (academicpaperwriter.com)
  • The Chi-Square distribution is a special case of the Gamma distribution [link to gamma]. (ucla.edu)
  • Random variate generator for gamma distribution. (haskell.org)
  • Note that the multivariate normal distribution is not a mere composite of univariate normal distributions. (gsu.edu)
  • Distribution for random variables constrained to be equal to or greater than 0 and which (unlike normal distribution) traces an asymmetric curve. (businessdictionary.com)
  • Probability Distributions An example will make clear the relationship between random variables and probability distributions. (slideplayer.com)
  • Cumulative Probability Distributions A cumulative probability refers to the probability that the value of a random variable falls within a specified range. (slideplayer.com)
  • The simplest probability distribution occurs when all of the values of a random variable occur with equal probability. (slideplayer.com)
  • Be able to apply various limit theorems to prove convergence in probability or in distribution of a sequence of random variables. (york.ac.uk)
  • Pseudo-random number generation for non-uniform distributions. (haskell.org)
  • Random variate generator for the chi square distribution. (haskell.org)
  • If the mean is nonzero, then the variable follows a noncentral distribution. (gsu.edu)
  • Discrete distributions have nonzero probability only at discrete points. (maplesoft.com)
  • Calculates any one parameter of the non-central chi-square distribution given values for the others. (scilab.org)
  • Create a probability distribution object using specified parameter values. (mathworks.com)
  • stats_cdf_beta - Calculates any one parameter of the beta distribution given values for the others. (php.net)
  • continuous distribution describes events over a continuous range, where the probability of a specific outcome is zero. (mcgill.ca)
  • A smooth function that describes the probability of landing anywhere on the dartboard is the probability distribution of the dart throwing event. (mcgill.ca)
  • 2011. On the distribution of sample measure of multivariate kurtosis. (springer.com)