Selection differences are likely to occur whenever researchers
A) use pre-existing groups found in natural settings.
B) fail to randomly assign participants to groups.
C) allow participants to assign themselves to groups.
D) fail to use random assignment.

Question

Quizplus · Accepted Answer

Selection differences occur when participants are not randomly assigned to groups. If participants are allowed to self-assign or if pre-existing groups are used, the likelihood of selection differences also increases. However, the most significant factor is the lack of random assignment.

Selection Differences Are Likely to Occur Whenever Researchers