Question

in a study designed to test the effectiveness of a medication as a treatment for lower back pain, 1643 patients were randomly assigned to one of three groups: (1) the 547 subjects in the placebo group were given pills containing no medication; (2) 550 subjects were in a group given pills with the medication taken at regular intervals; (3) 546 subjects were in a group given pills with the medication to be taken when needed for pain relief. in what specific way was replication applied in the study? choose the correct answer below. a. the group sample sizes are all large so the researchers could see the effects of the treatment. b. the researchers did not know whether the subjects in the study were taking a placebo or the medication. c. the subjects were divided into three groups so the researchers could compare the effects of the different treatments. d. the subjects in the study did not know whether they were taking a placebo or the medication.

Explanation:

Replication in a study often involves having large enough sample groups to observe treatment effects. Here, the three groups (placebo, regular medication, as - needed medication) have relatively large sample sizes (547, 550, 546). Option A states that the group sample sizes are all large so the researchers could see the effects of the treatment, which fits the concept of replication (having sufficient sample size to detect treatment effects). Option B is about blinding (researchers not knowing treatment assignment), Option C is about experimental design (dividing into groups for comparison), and Option D is about blinding of subjects. So the correct answer is A.

Answer:

A. The group sample sizes are all large so the researchers could see the effects of the treatment.