Answer:
c. The researcher must compute an estimated standard error for the mean difference score to compute a t statistic.
Explanation:
As already defined that repeated-measures experiments measure the same set of research participants two or more times, while matched-subjects experiments study participants who are matched on one or more characteristics.
Both repeated-measures experiment and a matched-subjects experiment when used to compare two treatment conditions use the same t statistic. Therefore, researcher must compute an estimated standard error for the mean difference score to compute a t statistic.