# Find the power of a race x treatment test. 25\% of patients will
# be non-white and the total sample size is 14000.
# Accrual is for 1.5 years and minimum follow-up is 5y.
# Reduction in 5-year mortality is 15\% for whites, 0\% or -5\% for
# non-whites. 5-year mortality for control subjects if assumed to
# be 0.18 for whites, 0.23 for non-whites.
n <- 14000
for(nonwhite.reduction in c(0,-5)) {
cat("% Reduction in 5-year mortality for non-whites:",
nonwhite.reduction, "")
pow <- ciapower(5, .75*n, .25*n, .18, .23, 15, nonwhite.reduction,
1.5, 5)
cat("Power:",format(pow),"")
}
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