Question 5 • Statistical Modeling - Content Recovery - Part B
A doctor wants to determine if a new medication for cholesterol is more effective than the previous medication. The doctor informs patients of a new medication and asks if they want to participate; 30 patients who are currently taking medication for cholesterol volunteer to be part of the study. She uses random assignment of the 30 patients to two treatment groups: one that uses the new medication, and one that uses the original medication. Which of the following describes the benefit of random assignment?
Answer
A
The variability between the medications would be evenly distributed between the two groups, so any observed differences in the cholesterol level between the two groups would more likely be due to the subjects.
B
The variability between the medications would be evenly distributed between the two groups, so any observed differences in the cholesterol level between the two groups would be guaranteed to be due to the subjects.
C
The variability between the subjects would be evenly distributed between the two groups, so any observed differences in the cholesterol level between the two groups would more likely be due to the new medication.
D
The variability between the subjects would be evenly distributed between the two groups, so any observed differences in the cholesterol level between the two groups would be guaranteed to be due to the new medication.
Explanation
Random assignment helps distribute differences among the patients—such as age, health, or starting cholesterol levels—between the two groups. This makes the groups more comparable, so an observed difference in cholesterol is more likely to be due to the new medication rather than preexisting differences between patients. It cannot guarantee that the medication caused the difference, which is why D is incorrect.
AI-written and checked against the verified answer.