A school counselor claims that he has developed a technique to reduce pre-studying 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.Suppose the counselor found the sum of squared deviations from the mean of the sample to be 135. Given that he tested 10 people, what would the estimated population variance be?
A. 135/10=13.5
B. 135/9=15.0
C. 10/135=0.70
D. 9/135=0.70