Step 1 :Determine whether the samples are independent or dependent. The problem states that to test the effectiveness of a drug, cholesterol levels are measured in 120 men before and after the treatment.
Step 2 :Choose the correct answer from the following options: A. The samples are independent because there is a natural pairing between the two samples. B. The samples are dependent because there is a natural pairing between the two samples. C. The samples are dependent because there is not a natural pairing between the two samples. D. The samples are independent because there is not a natural pairing between the two samples.
Step 3 :The correct answer is B. The samples are dependent because there is a natural pairing between the two samples. This is because the same men are measured before and after the treatment, creating a natural pairing.
Step 4 :\(\boxed{\text{The correct answer is B. The samples are dependent because there is a natural pairing between the two samples.}}\)