```
# 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("\n\n\n% Reduction in 5-year mortality for non-whites:",
nonwhite.reduction, "\n\n")
pow <- ciapower(5, .75*n, .25*n, .18, .23, 15, nonwhite.reduction,
1.5, 5)
cat("\n\nPower:",format(pow),"\n")
}
```

Run the code above in your browser using DataLab