If the Treatment Is a Two-Level Within-Subjects Factor and Counterbalancing

Multiple Choice

If the treatment is a two-level within-subjects factor and counterbalancing is the between-subjects factor, a significant interaction between treatment and counterbalancing tells you

A) very little
B) that a between-subjects design should have been used instead
C) that subjects getting one sequence of treatments (A-B) had a different total score than subjects getting another sequence (B-A)
D) that subjects tended to score differently on their first trial than they did on their second trial