9) One way to lessen the probability of non-equivalent groups is:
A) To randomly allocate all participants to conditions
B) To counterbalance conditions
C) To put participants who arrive early into one condition and later arrivals into the other
D) To make sure each group has the same average level of IQ

Question

Quizplus · Accepted Answer

Randomly allocating all participants to conditions is the best way to lessen the probability of non-equivalent groups because it ensures that any individual differences between participants are spread out equally across the conditions, making it unlikely that one condition will have an advantage over the other. Counterbalancing is also a useful technique, but it may not be possible or practical in all situations. Putting participants who arrive early into one condition and later arrivals into the other is not a reliable method of group allocation and may introduce bias into the study. Making sure each group has the same average level of IQ is not a feasible method since IQ is not easily manipulable and should not be used as a criterion for group allocation.

9) One Way to Lessen the Probability of Non-Equivalent Groups