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,

(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.