Solved: Exercises 41 through 44 refer to a clinical study conducted at the Houston

Chapter 14, Problem 41

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Exercises 41 through 44 refer to a clinical study conducted at the Houston Veterans Administration Medical Center on the effectiveness of knee surgery to cure degenerative arthritis (osteoarthritis) of the knee. Of the 324 individuals who met the inclusion criteria for the study, 144 declined to participate. The researchers randomly divided the remaining 180 subjects into three groups: One group received a type of arthroscopic knee surgery called debridement; a second group received a type of arthroscopic knee surgery called lavage; and a third group received skin incisions to make it look like they had had arthroscopic knee surgery, but no actual surgery was performed. The patients in the study did not know which group they were in and in particular did not know if they were receiving the real surgery or simulated surgery. All the patients who participated in the study were evaluated for two years after the procedure. In the two-year follow-up, all three groups said that they had slightly less pain and better knee movement, but the fake surgery group often reported the best results. [Source: New England Journal of Medicine, 347, no. 2 (July 11, 2002): 8188.](a) Describe as specifically as you can the target populationfor this study. (b) Describe the sample.