Harry decides to use incomplete counterbalancing for his study in which each participant is exposed to six different treatments over the course of the study. He decides to randomly select the sequences he will use. Which requirement of counterbalancing is he likely to violate?
a. Each treatment must be presented to each participant an equal number of times.
b. Each treatment must occur an equal number of times at each testing or practice session.
c. Each treatment must precede and follow each of the other treatments an equal number of times.
d. Both b and c.
