In a study that seeks to evaluate the effect that caffeine has on individuals with narcolepsy, 40 patients with this condition are randomly selected to participate in the study.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 variable of interest in this study is:
A) the 40 narcoleptic patients.
B) the period of 30 days.
C) the dosage of caffeine administered.
D) the sample size used.

Question

Quizplus · Accepted Answer

The variable of interest in this study is the effect that caffeine has on individuals with narcolepsy. In order to evaluate this effect, three different doses of caffeine are administered to three different groups of individuals. Therefore, the dosage of caffeine administered is the variable of interest in this study. The other options (A, B, and D) are not the main variable being studied, but rather they are other aspects of the study design such as the study population, the duration of the study, and the sample size used.

In a Study That Seeks to Evaluate the Effect That