A Researcher Is Interested in Testing the Effectiveness of a New

Multiple Choice

A researcher is interested in testing the effectiveness of a new approach to leading discussion groups in his classes.He assigns all the females in one of his classes to use the new discussion method and all the males to use the old discussion method.The researcher will not be able to interpret the results because his study is flawed due to

A) his having limited the boundary of generalizing his results.
B) the fact that he tested only one of his classes.
C) his failure to manipulate an independent variable.
D) the confounding of gender and discussion methoD.