A Counseling Psychologist Developing a Technique to Reduce Procrastination Has

Multiple Choice

A counseling psychologist developing a technique to reduce procrastination has students time their procrastination for a week and uses this as a pretest measure of procrastination. Students then attend a workshop in which they are instructed to do a specific warm-up exercise for studying by focusing on a pleasant activity. Students again time their procrastination for a week, and the time from this second week is the posttest measure.
-If the psychologist finds that the sum of squared deviations from the mean of the difference scores of the sample is 135,the estimated population variance would be

A) 135 / 10 = 13.5
B) 135 / 9 = 15.0
C) 10 / 135 = .074
D) 9 / 135 = .067