A school psychologist is using a depression inventory—on which a score of 0 indicates no depression and a score of 10 indicates severe depression—to see if the level of depression in fourth graders in a particular class of 20 students differs from that of fourth graders in general at a school. The results of previous testing indicate that fourth graders at the school usually have a score of 5 on the scale, but the variation is unknown. The current sample of 20 fifth graders has a mean depression score of 4.4.
-If the psychologist figures S = .85,the effect size (d)is
A)5 / .85 = 5.88
B).85 / 5 = 0.17
C)(5 - 4.4)/ .85 = 0.71
D).85 / (5 - 4.4)= 1.42

Question

Quizplus · Accepted Answer

The effect size (d) is calculated by taking the difference between the mean score of the sample and the mean score of the population, then dividing by the standard deviation of the sample. Thus, (5 - 4.4) / .85 = 0.71.

A School Psychologist Is Using a Depression Inventory—on Which a Score