| confounding variable | A variable that is not controlled in a research investigation. In an experiment, the experimental groups differ on both the independent variable and the confounding variable.
|
 |
|
|
| construct validity | The degree to which a measurement device accurately measures the theoretical construct it is designed to measure.
|
|
|
|
| correlation coefficient | An index of how strongly two variables are related to each other.
|
|
|
|
| curvilinear relationship | A relationship in which increases in the values of the first variable are accompanied by both increases and decreases in the values of the second variable.
|
|
|
|
| dependent variable | The variable that is the subject's response to, and dependent on, the level of the manipulated independent variable.
|
|
|
|
| experimental method | A method of determining whether variables are related, in which the researcher manipulates the independent variable and controls all other variables either by randomization or by direct experimental control.
|
|
|
|
| external validity | The degree to which the results of an experiment may be generalized.
|
|
|
|
| field experiment | An experiment that is conducted in a natural setting rather than in a laboratory setting.
|
|
|
|
| independent variable | The variable that is manipulated to observe its effect on the dependent variable.
|
|
|
|
| negative linear relationship | A relationship in which increases in the values of the first variable are accompanied by decreases in the values of the second variable.
|
|
|
|
| nonexperimental method | Use of measurement of variables to determine whether variables are related to one another. Also called correlational method.
|
|
|
|
| operational definition | Definition of a concept that specifies the operation used to measure or manipulate the concept.
|
|
|
|
| positive linear relationship | A relationship in which increases in the values of the first variable are accompanied by increases in the values of the second variable.
|
|
|
|
| randomization | Controlling for the effects of extraneous variables by ensuring that the variables operate in a manner determined entirely by chance.
|
|
|
|
| third variable | When describing the relationship between two variables, a third variable is any other variable that is extraneous to the two variables of interest. True experiments control for the possible influence of third variables.
|
|
|
|
| variable | Any event, situation, behavior, or individual characteristic that varies—that is, has at least two values.
|