Question

A study was done comparing the effectiveness of exercise vs medication on lowering

blood pressure in patients with high blood pressure. Two hundred subjects were randomly assigned to two groups. One group was instructed to exercise according to strict schedule, and the other group was given medication to take. After 3 months, the researchers compared the change in blood pressure between the groups and found that the exercise groups experienced a greater drop in blood pressure on average.

a. Is this an observational study or an experimental study?

b. Explain why a blind study is not possible in this situation.

Answer 1

a)

In an observational study, we measure or survey members of a sample without trying to affect them.

In a controlled experiment, we assign people or things to groups and apply some treatment to one of the groups, while the other group does not receive the treatment.

This is clearly an experimental study as two groups have been assigned two different activities and then observations are made.

b)

Blind Study is a study done in such a way that the patients or subjects do not know (is blinded as to) what treatment they are receiving to ensure that the results are not affected by a placebo effect (the power of suggestion).

Here, it is not possible as people are performing tasks, which are exercise and meditation and hence, it can not be done without their knowing of it.