To test the effects of drugs and alcohol use on driving performance, 20 volunteers were each asked to take a driving test under three conditions: sober, after two drinks, and after smoking marijuana. The order in which they drove the three conditions was randomized. An evaluator watched them drive on a test course and rated their accuracy on a scale from 1 to 10, without knowing which condition they were under each time.
a. What was the explanatory variable in this experiment?
b. What was the response variable in this experiment?
c. Was this experiment single-blind, double-blind, or neither? Explain
d. Did this experiment use matched pairs, blocks, or neither? Explain.