EBD 60`1 Ch.9

intervening variable

A variable (e.g., anxiety) that intervenes between or alters the relation between an independent variable and a dependent variable but that cannot be directly observed or controlled.

relationship study

An attempt to gain insight into the variables, or factors, that are related to a complex variable, such as academic achievement, motivation, or self-concept.

pearson r

A measure of correlation appropriate when both variables are expressed as continuous (i.e., ratio or interval) data; it takes into account every score and produces a coefficient between 21.00 and 11.00.

predictor

In a prediction study or analysis of concurrent or predictive validity, the variable on which the prediction is based.

cross-validation

Validation of a prediction equation with at least one group other than the group on which it was developed; results in the removal from the equation of variables no longer found to be related to the criterion measure.

multiple regression equation

A prediction equation using two or more variables that individually predict a criterion to make a more accurate prediction. Also called multiple prediction equation.

attenuation

The reduction in correlation coefficients that tends to occur if the measures being correlated have low reliability.

spearman rho

A measure of correlation appropriate when the data for at least one variable is expressed as rank or ordinal data; it produces a coefficient between 21.00 and 11.00.

prediction study

An attempt to determine which of a number of variables are most highly related to a criterion variable, a complex variable to be predicted.

criterion

The predicted variable that must be a valid measure of the performance to be predicted.

common variance

The variation in one variable that is attributable to its tendency to vary with another variable. Also called shared variance.

correlational research

Research that involves collecting data to determine whether, and to what degree, a relation exists between two or more quantifiable variables.

shrinkage

The tendency of a prediction equation to become less accurate when used with a group other than the one on which the equation was originally developed.

statistical significance

The conclusion that results are unlikely to have occurred by chance—that is, that the observed relation or difference is probably a real one.