Question

Each of the following quotes is based on the results of an experiment or an observational study. Explain which was used. If an observational study was used, explain whether an experiment could have been used to study the topic instead.

a) “A recent study of more than 6000 men found that having diabetes was a stronger predictor of risk of death than high cholesterol.”

b) “In a three-month study, researchers randomly assigned 250 black men and women to one of four groups: one received a placebo and the others received 1000, 2000, or 4000 international units of vitamin D daily [to see if vitamin D helps reduce hypertension in African-Americans]. The effect was modest.” (New York Times, March 19, 2013, p. D4).

Answer 1

Solution-

(A) of the following quotes is based on the results of an Observational study. (i.e. The observational study was used here).

In this case the cohort study have been used to study the topic.

(B) of the following quotes is based on the results of an Experimental study. (i.e. The experimental study was used here).

Here the Randomised controlled trial (RCT) have been used to study the topic. In this case the eligible peoples are randomly assigned to one or more groups.one receives intervention while the other receives placebo. Here the researcher randomly assigned 250 black men and women to one of four groups, one received a placebo and others received 1000,2000 or 4000 international units of vitamin D daily. The effect was modest.