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We wish to design a longitudinal study to assess risk factors for stroke. One primary outcome...

We wish to design a longitudinal study to assess risk factors for stroke. One primary outcome of the study is incident of stroke. In patients over the age of 65, approximately 14% develop stroke over 25 years. How many participants over the age of 65 must be enrolled to ensure the following?

  1. That we have 80% power to detect a 25% reduction in incidence of stroke between participants who participate in a healthy aging program as compared to those who do not. Assume that the incidence of stroke is 14% in those who do not participate.
  1. How many participants over the age of 65 should be enrolled to satisfy (a) assuming that 20% will be lost to follow-up over the course of the 25-year follow-up?
Math   Statistics-And-Probability   
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