Controlling Within-Subjects Designs If an experimenter plans to use complete counterbalancing with five levels of an independent variable, she will need a minimum of ___ subjects.
A)5
B)15
C)40
D)120

Question

Quizplus · Accepted Answer

Complete counterbalancing requires using all possible orders of conditions. With 5 levels, there are 5! (5 factorial) = 120 possible orders, so 120 subjects are needed to cover each order once.

Controlling Within-Subjects Designs If an Experimenter Plans to Use Complete