Which of the following statements is correct about random assignment in a posttest-only experimental design:
A) It never provides an adequate basis for supposing that both groups would have had very similar pretest scores.
B) It always provides an adequate basis for supposing that both groups would have had very similar pretest scores.
C) It provides an adequate basis for supposing that both groups would have had very similar pretest scores only when the sample size is large enough to permit such a supposition.
D) None of the above.

Question

Quizplus · Accepted Answer

Random assignment helps ensure that groups are comparable at the start of an experiment, but this assumption is more reliable with larger sample sizes.

Which of the Following Statements Is Correct About Random Assignment