One hundred volunteers who suffer from severe depression are available for a study.Fifty are selected at random and are given a new drug that is thought to be particularly effective in treating severe depression.The other 50 are given an existing drug for treating severe depression.A psychiatrist evaluates the symptoms of all volunteers after 4 weeks in order to determine if there has been substantial improvement in the severity of the depression.Suppose volunteers were first divided by gender,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 other drug.What is this an example of?

Question

Quizplus · Accepted Answer

This is an example of a block design where the volunteers were divided into two blocks based on gender and then randomly assigned to the two drugs within each block. This design helps to control for the potential confounding effect of gender on the outcome of the study.

One Hundred Volunteers Who Suffer from Severe Depression Are Available