For the following question(s): A school counselor claims that he has developed a technique to reduce prestudying procrastination in students. He has students time their procrastination for a week and uses this as a pretest (before)indicator of procrastination. Students then attend a workshop in which they are instructed to do a specific warming-up exercise for studying by focusing on a pleasant activity. For the next week, students again time their procrastination. The counselor then uses the time from this week as the posttest (after)measure.
-A researcher conducts a t test for dependent means with 10 participants. The estimated population variance of the change scores is 20. What is the variance of the distribution of the means of change scores?
A)20/10 = 2.0
B)20/9 = 2.2
C)400/10 = 40.0
D)400/9 = 44.4

Question

Quizplus · Accepted Answer

The variance of the distribution of the means of change scores is equal to the variance of the change scores divided by the sample size. In this case, the variance of the change scores is 20 and the sample size is 10, so the variance of the distribution of the means of change scores is 20/10 = 2.0.

For the Following Question(s): a School Counselor Claims That He