To determine if topiramate is a safe and effective treatment for alcohol dependence, researchers conducted a 14-week trial of 371 men and women aged 18 to 65 years diagnosed with alcohol dependence. In this double-blind, randomized, placebo-controlled experiment, subjects were randomly given either 300 milligrams (mg) of topiramate (183 subjects) or a placebo (188 subjects) daily, along with a weekly compliance enhancement intervention. The variable used to determine the effectiveness of the treatment was self-reported percentage of heavy drinking days. Results indicated

that topiramate was more effective than placebo at reducing the percentage of heavy drinking days. The researchers concluded that topiramate is a promising treatment for alcohol dependence.

(a) What does it mean for the experiment to be placebo-controlled?

(b) What does it mean for the experiment to be double-blind? Why do you think it is necessary for the experiment to be double-blind?

(c) What does it mean for the experiment to be randomized?

(d) What is the population for which this study applies? What is the sample?

(e) What are the treatments?

(f ) What is the response variable?