How many groups of participants would be needed to completely counterbalance a within-subjects experiment with three treatment conditions?
A)1
B)3
C)6
D)9

Question

Quizplus · Accepted Answer

In a within-subjects design, each participant is exposed to all treatment conditions, meaning that counterbalancing is necessary to ensure that the order of treatment conditions does not affect the results. To achieve complete counterbalancing, each possible sequence of treatments would need to be tested. With three treatment conditions, there are six possible orders (ABC, ACB, BAC, BCA, CAB, CBA), so at least six groups of participants would be needed for complete counterbalancing.

How Many Groups of Participants Would Be Needed to Completely