Professor Golder Is Studying Hyperactivity in Preschool-Age Children

Multiple Choice

Professor Golder is studying hyperactivity in preschool-age children. She is concerned that differences in child rearing, diet, and so forth may affect her results. To minimize these potential preexisting variables, she should be sure to do which of the following?

A) Use random assignment when forming her groups.
B) Include an independent variable.
C) Include a dependent variable.
D) Assign boys to the experimental group and girls to the control group.