Power and Sample Size with spower from Hmisc


          

We simulate a 2-arm 5-year follow-up study using Hmisc. All subjects are followed at least one year, and patients enter the study with linearly increasing probability starting with zero. Assume (1) there is no chance of dropin for the first 6 months, then the probability increases linearly up to .15 at 5 years; and (2) there is a linearly increasing chance of dropout up to .3 at 5 years.

Instructions

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