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

Question

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

Quizplus · Accepted Answer

I. Randomization indeed reduces the effects of confounding variables by ensuring that any such variables are equally distributed across treatment groups, thus minimizing their impact on the outcome. III. Blocking is a technique used to group similar experimental units together and then randomize within these blocks, which helps to reduce the variability within treatment groups, making it easier to detect treatment effects. II is incorrect because random assignment of treatments ensures that the treatment groups are comparable, but it does not guarantee that the results can be generalized to the larger population; generalizability depends on how representative the sample is of the population, not on the random assignment of treatments.

Which Is True About Randomized Experiments