A Study of a Drug to Prevent Hair Loss Showed

Multiple Choice

A study of a drug to prevent hair loss showed that 86% of the men who took it maintained or increased the amount of hair on their heads. But so did 42% of the men in the same study who took a placebo instead of the drug. This is an example of

A) a sampling error: The study should not have included men whose hair grew without the drug.
B) the placebo effect.
C) an error in calculating percentages.
D) failure to use the double-blind idea.