independent variable (redirected from Independent variables)

independent variable,

(in research) a variable that is manipulated (controlled) by the researcher and evaluated by its measurable effect on the dependent variable or variables. For example, in a study of the effect of nursing intervention on postoperative vomiting, nursing intervention is the independent variable evaluated by its effect on the dependent variable, the incidence of postoperative vomiting. Also called experimental variable, predictor variable. Compare dependent variable.

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variable [var´e-ah-b'l]

something that changes; an attribute or property of a person, event, or object that is known to vary in a given study.

dependent variable in a mathematical equation or relationship between two or more variables, a variable whose value depends on those of others; it represents a response, behavior, or outcome that the researcher wishes to predict or explain.

extraneous variable a factor that is not itself under study but affects the measurement of the study variables or the examination of their relationships.

independent variable in a mathematical equation or relationship between two or more variables, any variable whose value determines that of others; it represents the treatment or experimental variable that is manipulated by the researcher to create an effect on the dependent variable.

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variable,

adj 1. changing; able to vary in quantity or magnitude.
n 2. a characteristic that may assume several values.

variable, continuous,

n a variable for which it is possible to find an intermediate value between any two values. Continuous variables can be refined by more precise values. Length, weight, and time, and the points on a line are continuous variables.

variable costs,

n costs, such as dental service claims, that generally increase or decrease as the size and composition of the enrollment fluctuates.

variable, dependent,

n a variable whose value is consequent on change in the independent variable. The dependent variable is always the response or reaction to the independent variable. Also called
criterion variable.

variable, discrete,

n a variable that is expressed in whole units or mutually exclusive categories. Whole numbers and category designations such as sex and marital status are examples of discrete data.

variable, independent,

n the variable being studied that is manipulated or controlled by an experimenter. In a drug study an investigator may give several doses of a drug (independent variable) to determine the most effective, symptom-reducing (dependent variable) level.

variables, control,

n.pl those variables not being studied that are held constant so as not to influence the experimental outcome. Environmental conditions, intelligence quotients, and social and psychologic variables are examples of variables that must be controlled.

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variable

1. any type of measurement, quantitative or qualitative, of which a series of individual observations is made so that it has, as a principal characteristic, the potential for variability.

2. has the quality of variability.

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variable agent

an agent in the cause of a disease which is capable of variation in intensity, e.g. weather, as contrasted to one that is not variable, e.g. Salmonella dublin.

concomitant v's

in experimental design these refer to factors that affect the dependent variable, but are not themselves influenced by the treatment (e.g. age of animal). The effect of concomitant variables can be removed by suitable experimental design or by including them in the model.

continuous variable

one in which all values within a given range are possible, e.g. birth weights of calves.

variable costs

costs which vary with the dimensions of the activity. Includes seed, fertilizer, teat dip, worm drench. Called also direct costs. See also fixed costs.

dependent variable

1. in statistics the variable predicted by a regression equation.

2. a variable which depends on other variables for its value.

discontinuous variable

see discrete variable (below).

discrete variable

one in which the possible values are not on a continuous scale, e.g. the number of sheep in a flock.

endogenous variable

dependent variable.

exogenous variable

independent or predetermined variable.

independent variable

one not dependent on other variables but capable of affecting dependent variables, thus an input variable.

spatial variable

a measurement relating to area or location.

temporal variable

one relating to chronological time.