Which Is True About Randomized Experiments

Multiple Choice

Which is true about randomized experiments?
I. Randomization reduces the effects of confounding variables.
II. Random assignment of treatments allows results to be generalized to the larger population.
III. Blocking can be used to reduce the within-treatment variability.

A) III only
B) II only
C) I only
D) I, II, and III
E) I and III