Natasha wants to know whether wearing sunglasses helps while driving. In a counterbalanced repeated measures design, presence or absence of sunglasses would be varied by:
A)having half the drivers drive with sunglasses and the other half drive without sunglasses.
B)having all drivers first drive without sunglasses and then with sunglasses.
C)having half the drivers first drive without sunglasses and then with sunglasses and having the other half first drive with sunglasses and then without sunglasses.
D)having all drivers first drive with sunglasses and then without sunglasses.

Question

Quizplus · Accepted Answer

In a counterbalanced repeated measures design, it is important to counterbalance the order of conditions to control for order effects. This means that half the drivers should start with the condition (sunglasses or no sunglasses) that the other half ends with. Therefore, option C is the best choice as it counterbalances the order for all drivers. Option A does not counterbalance the order as only half the drivers wear sunglasses, and option B does not counterbalance the order as all drivers start with the same condition. Option D also does not counterbalance the order as all drivers start with the same condition.

Natasha Wants to Know Whether Wearing Sunglasses Helps While Driving