= One sample t-test in R =

For a (two-tailed) type I error, alpha, testing a sample of size n with mean and sd we can obtain the power as below in R. These results agree with this
[[http://www.stat.ubc.ca/~rollin/stats/ssize/n1.html|on-line calculator.]]

Copy and Paste the below into R.
{{{
fn <- function (alpha,mean,sd,n) {
pow <- 1 - pt(abs(qt(alpha/2, n-1)), n-1, (mean/sd)*sqrt(n))
cat("Power of (two-sided) equal groups unpaired t-test is")
print(pow)
 }
}}}
Specify inputs:
{{{
alpha <- 0.05
mean <- 1
sd <- 4
n <- 130
}}}
and run
{{{
fn(alpha,mean,sd,n)
}}}