| regression analysis | 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. (12 Dec 1998) |
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| regression | 1. A return to a former or earlier state. 2. A subsidence of symptoms or of a disease process. 3. <psychiatry> A return to earlier, especially to infantile, patterns of thought or behaviour, a characteristic of many mental disorders also exhibited by normal persons in many situations, for example feelings of helplessness and dependency in a patient with a serious physical illness. Origin: L. Regressio = a return (18 Nov 1997) |
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| regression of the mean | If, for a symmetrical population with a single mode, a measurement, selected because it is extreme, is repeated, on average the second reading will be closer to the mean than the first. (05 Mar 2000) |
| phonaemic regression | A decrease in intelligibility of speech associated with an increase in loudness. (05 Mar 2000) |
| mullerian regression factor | Mullerian duct inhibitory factor, a non-steroidal substance of foetal testicular origin that acts unilaterally to inhibit development of the paramesonephric (mullerian) ducts and acts with testosterone to promote development of the vas deferens and related structures. (05 Mar 2000) |
| corpus luteum regression | Involution and cessation of endocrine function of a corpus luteum. (12 Dec 1998) |
| neoplasm regression, spontaneous | Disappearance of a neoplasm or neoplastic state without the intervention of therapy. (12 Dec 1998) |
| law of regression to mean | In a population mating at random, the progeny of a parent with an extreme value for a measurable phenotype will tend on average to have values nearer the population mean than in the extreme parent. See: law of regression to mean. Synonym: law of regression to mean. (05 Mar 2000) |
| accumulation analysis | A technique in which an intermediate of a metabolic pathway accumulates due to selective inhibition of a particular step in that pathway or in a mutant that is deficient in a certain step. The intermediate is then isolated, analyzed, and identified. (05 Mar 2000) |
| activation analysis | <radiobiology> Method for identifying and measuring chemical elements in a sample of material. Sample is first made radioactive by bombardment with neutrons, charged particles, or gamma rays. Newly formed radioactive atoms in the sample then give off characteristic radiations (such as gamma rays) that tell what kinds of atoms are present, and how many. (09 Oct 1997) |
| actuarial analysis | The application of probability and statistical methods to calculate the risk of occurrence of any event, such as onset of illness, recurrent disease, hospitalization, disability, or death. It may include calculation of the anticipated money costs of such events and of the premiums necessary to provide for payment of such costs. (12 Dec 1998) |
| amino acid analysis | Determination and identification of amino acid content of a macromolecule, identification of a specific amino acid in macromolecules, often a mutated protein, identification and quantitation of amino acid content in blood plasma or urine; a key diagnostic aid. (05 Mar 2000) |
| analysis | <technique> The separation into component parts or elements, the act of determining the component parts of a substance. Origin: Gr. Lysis = dissolution (18 Nov 1997) |
| analysis of variance | A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable. (12 Dec 1998) |
| base sequence analysis | <molecular biology> A method, sometimes automated, for determining the base sequence. (09 Oct 1997) |
| bite analysis | A study of the relations of the occlusal surfaces of opposing teeth and their effect upon related structures. Synonym: bite analysis. (05 Mar 2000) |