Within-Subjects Variable (1 of 2)

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A within-subjects variable is an independent variable that is manipulated by testing each subject at each level of the variable. Consider an experiment examining the effect of study time on memory. Subjects are given a list of 10 words to study for later recall. In one condition, subjects are given one minute to study the list; in the other condition, subjects are given two minutes. Each subject is tested once in each condition. Therefore, subjects have two scores, one for the one-minute condition and one for the two-minute condition.(Naturally, subjects are given different lists of words each time. Half of the subjects are tested with the one-minute condition first; the other half are tested with the two-minute condition first). The variable "study time" is a within-subjects variable since each subject is tested under each of the two levels of the variable (one minute and two minutes). The same subjects are used in both conditions so the comparison between conditions can be made within each of the subjects.