What approximate percentage of federal prisoners are drug-law offenders?

The purpose of a control group in an experiment is to:

a. serve as a check on the interpretation of results. b. increase the ability to generalize the findings. c. manipulate the dependent variable. d. represent the general, nonlaboratory population.

Susan would like for her child to learn a second language. If she wants the child to be fluent in the second language, research suggests that she should begin instruction no later than age

A) three. B) five. C) seven. D) ten.