A study randomly assigned subjects to receive either St. John's wort extract (n = 98) or a placebo (n = 102). For each subject, the investigators assessed the person's rate of change in the Hamilton Rating Scale for Depression over the treatment period.
Which type of study is this?

Question

Quizplus · Accepted Answer

This is a completely randomized experiment since the subjects were randomly assigned to receive either the St. John's wort extract or a placebo.

A Study Randomly Assigned Subjects to Receive Either St