| models, statistical | 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. (12 Dec 1998) |
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| statistical distributions | The complete summaries of the frequencies of the values or categories of a measurement made on a group of items, a population, or other collection of data. The distribution tells either how many or what proportion of the group was found to have each value (or each range of values) out of all the possible values that the quantitative measure can have. (12 Dec 1998) |
| statistical genetics | The study of the applications of principles of statistics to problems in genetics. (05 Mar 2000) |
| statistical model | A formal representation for a class of processes that allows a means of analyzing results from experimental studies, such as the Poisson model or the general linear model; it need not propose a process literally interpretable in the context of the individual case. (05 Mar 2000) |
| statistical significance | Statistical methods allow an estimate to be made of the probability of the observed degree of association between variables, and from this the statistical significance can be expressed, commonly in terms of the P value. (05 Mar 2000) |
| Neyman-Pearson statistical hypothesis | A formal conjecture about the numerical value of a parameter to be tested exclusively in the light of an immediate set of data without attention to prior knowledge or convictions and ignoring other sets of evidence treated in a similar fashion. The answer is a statement not about whether the hypothesis is true but whether it is an acceptable explanation of the data or should be rejected in favour of another hypothesis. (05 Mar 2000) |
| data interpretation, statistical | Application of statistical procedures to analyze specific observed or assumed facts from a particular study. (12 Dec 1998) |
| Diagnostic and Statistical Manual | An American Psychiatric Association publication which classifies mental illnesses.Currently in its fourth edition (DSM-IV) and first published in 1952, the manual provides health practitioners with a comprehensive system for diagnosing mental illnesses based on specific ideational and behavioural symptoms. The DSM approach supplants older, less rigorous methods of diagnosis, and as such represents a major step forward for the field of psychiatry. It consists of five axes covering clinical syndromes, developmental and personality disorders, physical disorders, severity of psychosocial stressors, and global assessment of functioning. It is used primarily in the U.S.; elsewhere, the World Health Organization's International Classification of Diseases is preferred. (05 Mar 2000) |
| factor analysis, statistical | 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. (12 Dec 1998) |
| Abbe test plate | <equipment> A long, wedge-shaped coverslip about 0.20 mm thick at one end and 0.10 to 0.12 mm at the other end coated chemically with a silver film on which are ruled horizontal lines. at each variation in thickness of 0.01 mm there are vertical lines. By means of oblique illumination and by focusing on different portions of the plate, it is possible to determine the optimum coverslip thickness for any objective and also, for microscopes with drawtubes, the tube length for best objective performance. The approximate freedom from spherical and chromatic aberrations can also be estimated. Small isolated bits of silver near the edges of the lines form good objects for the star test (05 Aug 1998) |
| acetone test | A test for ketonuria; the suspected urine is shaken up with a few drops of sodium nitroprusside, and strong ammonia water is then gently poured over the mixture; if acetone is present, a magenta ring forms at the line of contact; tablets containing sodium nitroprusside and alkali are now more commonly used. (05 Mar 2000) |
| achievement test | A standardised test used to measure acquired learning, e.g., competence in a specific subject area such as reading or arithmetic, in contrast to an intelligence test which is a useful index of potential ability or learning. (05 Mar 2000) |
| acidified serum test | Lysis of the patient's red cells in acidified fresh serum, specific for paroxysmal nocturnal haemoglobinuria. Synonym: Ham's test. (05 Mar 2000) |
| acid loading test | <nephrology> This is a test used in the diagnosis of renal tubular acidosis. The patient takes ammonium chloride capsules for 3 days to acidify the blood (lower blood pH). A sample of the urine and the blood is then collected and the results are interpreted. (27 Sep 1997) |
| acid perfusion test | <gastroenterology, investigation> A test used to diagnosis gastrooesophageal reflux disease. This investigation requires that the patient swallow 3 tiny tubes into the stomach. A mixture of hydrochloric acid (like stomach acid) and saline are alternatively injected into the tubes. The patient then reports any symptoms they may have. Some patients may vomit. (13 Nov 1997) |