Regression to the Mean Is a Threat to the Internal

Multiple Choice

Regression to the mean is a threat to the internal validity of the pretest/posttest design whenever

A) a long time transpires between the two observation periods.
B) program participants get older between the two observations.
C) people are chosen for a program because initial observations showed that they needed the program more than others did.
D) evaluators gain experience making the observations for the pretest and the posttest.