A repeated-measures research study comparing two treatments with a set of 10 scores in each treatment will produce a t statistic with df = 18.

Question

Quizplus · Accepted Answer

In a repeated-measures design comparing two treatments, the degrees of freedom (df) for the t statistic are calculated based on the number of subjects, not the total number of scores across treatments. Since each subject contributes one pair of scores (one for each treatment), the df is calculated as the number of pairs minus one. If there are 10 pairs of scores (indicating 10 subjects), the df = 10 - 1 = 9.

A Repeated-Measures Research Study Comparing Two Treatments with a Set