| normal distribution | 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. (12 Dec 1998) |
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| dermatomal distribution | The area of skin innervated by a single posterior spinal nerve (sensory nerve). (27 Sep 1997) |
| distribution | 1. The specific location or arrangement of continuing or successive objects or events in space or time. 2. The extent of a ramifying structure such as an artery or nerve and its branches. 3. The geographical range of an organism or disease. 4. Probability. Origin: L. Distributio (11 Jan 1998) |
| distribution coefficient | The ratio of concentrations of a substance in two immiscible phases at equilibrium; the basis of many chromatographic separation procedures. Synonym: partition coefficient. (05 Mar 2000) |
| distribution curve | A systematic grouping of data into classes or categories according to the frequency of occurrence of each successive value or ranges of such values, resulting in a graph of a frequency distribution. Synonym: frequency curve. (05 Mar 2000) |
| distribution leukocytosis | An abnormally large proportion of one or more types of leukocytes. (05 Mar 2000) |
| distribution volume | The volume throughout which an added tracer substance appears to have been evenly distributed, calculated by dividing the amount of tracer added by its concentration after equilibration. (05 Mar 2000) |
| t distribution | The distribution of the quotient of independent random variables, the numerator of which is a standardised normal variate and the denominator the positive square root of the quotient of a chi-square distributed variate and its number of degrees of freedom. (05 Mar 2000) |
| tissue distribution | Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios. (12 Dec 1998) |
| epidemiological distribution | See: histogram. (05 Mar 2000) |
| exponential distribution | The time until failure of a process at constant hazard. (05 Mar 2000) |
| f distribution | The distribution of the ratio of two independent quantities each of which is distributed like a variance in normally distributed samples. So named in honor of the English statistician and geneticist R.A. Fisher. (05 Mar 2000) |
| frequency distribution | A statistical description of raw data in terms of the number or frequency of items characterised by each of a series or range of values of a continuous variable. (05 Mar 2000) |
| lognormal distribution | If a variable y is such that x = log y, it is said to have a lognormal distribution; this is a skew distribution. (05 Mar 2000) |
| acquired platelet function defect | <haematology> Platelet function can be affected by a number of different disease processes including polycythaemia vera, leukaemia, myelofibrosis, renal failure, multiple myeloma and some medications (for example penicillins, salicylates, phenothiazines). Disturbed blood clotting can be manifested by: easy bruising, bleeding gums, nosebleeds, abnormal vaginal bleeding, rectal bleeding, skin rash, vomiting blood, coughing up blood or blood in the urine. A measure of bleeding time and coagulation profile will be part of the evaluation. (29 Dec 1997) |