A meta-analysis examined studies that compared two types of mental health treatments for ethnic and racial minorities—the standard available treatments and treatments that were adapted to the clients’ cultures (Griner & Smith, 2006). An excerpt from the abstract follows:

Many previous authors have advocated traditional mental health treatments be modified to better match clients’ cultural contexts. Numerous studies evaluating culturally adapted interventions have appeared, and the present study used metaanalytic methodology to summarize these data. Across 76 studies the resulting random effects weighted average effect size was d = .45, indicating a. . . benefit of culturally adapted interventions.

a. What is the topic chosen by the researchers conducting the meta-analysis?

b. What type of effect size statistic did the researchers’ calculate for each study in the meta-analysis?

c. What was the mean effect size? According to Cohen’s conventions, how large is this effect?

d. If a study chosen for the meta-analysis did not include an effect size, what summary statistics could the researchers use to calculate an effect size?