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

Multiple Choice

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