One hundred sixty people who suffer from painful diabetic neuropathy have volunteered to participate in a study. Eighty are selected at random and are given the drug gabapentin, which (although originally intended to prevent epileptic seizures) has properties that may make it useful to alleviate neuropathy. The remaining participants are given a placebo. A neurologist evaluates the symptoms of all volunteers after two months to determine if there has been substantial improvement in the severity of the symptoms. Suppose the volunteers were first divided into men and women, and then half of the men were randomly assigned to the new drug and half of the women were assigned to the new drug. The remaining volunteers received the placebo. This would be an example of:
A)replication.
B)confounding-the effects of gender will be mixed up with the effects of the drug.
C)a block design.
D)a matched pairs design.

Question

Quizplus · Accepted Answer

This is a block design, where the participants are first divided into two blocks based on gender, and then each block is randomly assigned to either the drug or placebo group. This helps to control for any potential gender differences in response to the treatment, as each treatment group within a block will have equal proportions of men and women. Confounding is avoided by the use of blocks, as the gender effect is separated from the drug effect. Replication involves repeating the experiment several times to increase confidence in the results, and a matched pairs design would involve each participant receiving both the drug and placebo at different times to compare the effects within each individual.

One Hundred Sixty People Who Suffer from Painful Diabetic Neuropathy