Sample Design Literacy In “Cardiovascular Effects of Intravenous Triiodothyronine in Patients Undergoing Coronary Artery Bypass Graft Surgery” [Journal of the American Medical Association (JAMA), Vol. 275, No. 9], the authors explain that patients were assigned to one of three groups: (1) a group treated with triidothyronine, (2) a group treated with normal saline bolus and dopamine, and (3) a placebo group given normal saline. The authors summarize the sample design as “randomized and double-blind.” Describe the meaning of “randomized” and “double-blind” in the context of this study.

The three groups in the study:

(1) A group treated with triidothyronine

(2) A group treated with normal saline bolus and dopamine

(3) A placebo group administered normal saline

Randomization means assigning the participants to a certain number of groups following a random process.

Also, an experiment is said to be double-blind if the treatments allocated to the subjects are unknown to the participants as well as the person conducting the experiment.

In the study, the subjects are the patients of the study, and there are three groups of treatments.

When the patients are randomly assigned one of the three treatments, the experiment is said to be randomized.

Also, when the patients, as well as the person conducting the experiment, are unaware of the treatments being provided to the patients, the experiment is said to be double-blinded.