Question: Calculate the degrees of freedom for a related-samples t test and locate critical values in the t table; identify the assumptions for the related-samples t test; compute a related-samples t test and interpret the results.
• The related-samples t test is a statistical procedure used to test hypotheses concerning two related samples selected from related populations in which the variance in one or both populations is unknown.
• The degrees of freedom for a related samples t test is the number of difference scores minus 1: df= (nD -1).
• To compute a related-samples t test, we assume normality and independence within groups. The test statistic for a related-samples t test concerning the difference between two related samples is as follows: