18. You wish to compare the effectiveness of four methods for teaching metacognitive strate- 18.

gies to elementary school children. A group of 40 fifth graders is randomly divided into four subgroups, each of which is taught according to one of the different methods. You then individually engage each child in a “think aloud” problem-solving task, during which you record the number of metacognitive strategies the child invokes. The results are as follows: