To Conduct a Meta-Analysis,______

Multiple Choice

To conduct a meta-analysis,______.

A) there must be more than one study that has examined the effects of a given treatment
B) if at least one study included in the meta-analysis used a control group, other studies without control groups can be considered as well
C) a negative effect size indicates a reduction in symptoms among the treatment group
D) any effect size over 0.25 is considered large