An experiment was conducted to compare two procedures (A and B) for measuring a person's reaction time to a stimulus. Ten volunteers participated in the experiment, and each volunteer was given the stimulus twice. For each person the reaction time was measured once with procedure A and once with procedure B. as shown in DS 9.2.7. A reviewer comments that the differences between the reaction times obtained for procedures A and B can be explained by the fact that each time a person is given the stimulus the actual reaction time varies. Do you agree with the reviewer, or do you think that there is evidence that procedures A and B do give different readings on average?