Question

In the mid-1990s a study was conducted in which 10 men with arthritic knees were schedule for surgery. They were all treated exactly the same except for one key difference: only some of them actually had the surgery. Once each patient was in the operating room and anesthetized, the surgeon looked at a randomly generated code indicating whether to do the full surgery or just make three small incisions in the knee and stitch them up to leave a scar. All patients received the same post-operative care, rehabilitation, and were later evaluated by staff who didn't know which treatment they had. The result: The men getting the sham knee surgery had improvement that was not distinguishable from the men getting the real surgery.

Identify the treatments and the subjects

Answer 1

Treatments: In experiments/study, a treatment is something that researchers administer to experimental units. It is any level of an independent or explanantory variable which can be manipulated as per study objective.

Here, treatments are "surgery is done on the patients" and "just three incisions are made in the knee to leave a scar".
Treatment A: surgery done (real surgery)
Treatment B: surgery not done instead incisions in the knee. (sham surgery)

Subjects are the units on whom the treatment is applied. Here, the treatment is applied on 10 men with arthritic knees. Thus, "10 men" are the subjects.