1. Peripheral arterial disease involves blockages in one or more arteries in the leg. Patients with peripheral arterial disease typically experience pain while walking, and there are pote

1. Peripheral arterial disease involves blockages in one or more arteries in the leg. Patients with peripheral arterial disease typically experience pain while walking, and there are potentially serious complications associated with the disease. A group of investigators are interested in comparing the effect of a 12-week structured exercise therapy program versus stenting (a revascularization procedure for the leg) on the outcome “distance able to walk without pain” for patients with PAD.
a. What are the strengths and potential limitations of using a randomized clinical trial study design to test this hypothesis? Use your own words and answer the question in terms of the population, interventions, and outcome under consideration.
b. Briefly describe how the patients who are eligible but “refuse enrollment” could affect the internal validity or the generalizability of the study? Describe how patients who “discontinue intervention” could affect the internal validity or the generalizability of the study?