The article “Factors Associated with Exercise Behavior in People with Parkinson Disease” (T. Ellis, J. Cavanaugh, et al., Physical Therapy, 2011:1838–1848) reported a survey of patients with Parkinson’s disease. Of 164 patients who said they exercised regularly, 76 reported falling in the previous six months. Of 96 patients who said they did not exercise regularly, 48 reported falling in the previous six months. Can you conclude that the proportion of patients who fall is less for those who exercise than for those who do not?