In a Study That Seeks to Evaluate the Effect Caffeine

Multiple Choice

In a study that seeks to evaluate the effect caffeine has on narcoleptics,40 narcoleptic patients are randomly selected to participate.Fifteen of the patients are given high doses of caffeine,15 are given moderate doses,and 10 are given low doses over a period of 30 days.The total amount of time they slept over the 30 days was recorded.This is BEST described as a(n) _____ study.

A) voluntary
B) observational
C) dosage
D) experimental