A study is designed to test the effect of light level on exam performance of students. The researcher believes that light levels might have different eects on males and females, so wants to make sure both are equally represented in each treatment. The treatments are uorescent overhead lighting, yellow overhead lighting, no overhead lighting (only desk lamps).

(a) What is the response variable?

(b) What is the explanatory variable? What are its levels?

(c) What is the blocking variable? What are its levels?