- 1. That which is inconstant, which can or does change, as contrasted with a constant. 2. Deviating from the type in structure, form, physiology, or behavior. [L. vario, to vary, change, differ]- continuous random v. continuous v. that may randomly assume any value in its domain but any particular value has no probability of occurring, only a probability density.- dependent v. in experiments, a v. that is influenced by or dependent upon changes in the independent v.; e.g., the amount of a written passage retained (dependent v.) as a function of the different numbers of minutes (independent v.) allowed to study the passage.- discrete random v. a random v. that may assume a countable number of values, each with a probability strictly greater than zero.- independent v. a characteristic being measured or observed that is hypothesized to influence another event or manifestation (the dependent v.) within a defined area of relationships under study; that is, the independent v. is not influenced by the event or manifestation, but may cause it or contribute to its variation. See dependent v..- intermediate v. a v. in a causal pathway that causes variation in the dependent v. and is itself caused to vary by the independent v..- intervening v. an event, such as an attitude or emotion, inferred to occur within an organism between the stimulation and response in such a way as to influence or determine the response.- mixed discrete-continuous random v. a random v. that may assume some values with probabilities and others with probability densities. For example, in a 35-year-old man with familial polyposis of the colon, the distribution of time until malignant disease occurs consists of a probability that he already has cancer (which would be assigned the waiting time 0), a probability density of developing it in the future, and a probability that he will die of some other cause before he develops cancer.- moderator v. a v. that interacts by virtue of being antecedent or intermediate in the causal pathway.- random v. a v. that may assume a set of values, each with fixed probabilities or probability densities (its distribution), in such a way that the total probability assigned to the distribution is unity; the random v. may be discrete, continuous, or mixed discrete-continuous.
* * *vari·able 'ver-ē-ə-bəl, 'var- adj1) able or apt to vary: subject to variation or changes <allergy is perhaps the most \variable of all diseases (H. G. Rapaport & Shirley Linde)>2) characterized by variations3) not true to type: ABERRANT used of a biological group or charactervariable n something that is variable
* * *n.(in biostatistics) a characteristic (e.g. morbidity, lifestyle, or habit) relating to a single individual or group. Qualitative variables are descriptive characteristics, such as sex, race, or occupation; quantitative variables relate to a numerical scale and are subdivided into discrete variables, found only at fixed points (e.g. number of children), and continuous variables, found at any point on a scale (e.g. weight).
* * *var·i·a·ble (varґe-ə-bəl) [L. variare to change] 1. changing from time to time. 2. in mathematics, a symbol that represents an arbitrary number or an arbitrary element of a set.
Medical dictionary. 2011.