R standard error

[jmaccherone]

For known population, based on statistical proofs.

There is not a function in R for this (that I know of), but the book suggests that you calculate standard error by calculating (standard deviation(population)/square root (sample size).

Then you would make cut points at 97.5% and 2.5%.

The 97.5% cut point would be (mean + 2 * standard error) and the 2.5% cut point would be (mean - 2*standard error).