Today’s task is to compute a statistical power function in R. For a good definition of power, go here. Thinking about the power of a testing procedure is an often-overlooked aspect of hypothesis testing.

I also explain what power (in a statistical sense) is in the video, as well as use my shadenorm() function to show what power looks like on the classical hypothesis testing graph. Along the way, I demonstrate how writing a function can make your life easier. Here’s the video:



Here is the script file I walk through in the video (copy into notepad for a better view):



My script file uses a new version of my shadenorm() command that is a little easier to use (only change: now, there are no justbelow or justabove arguments. If you just specify below, that’s justbelow=TRUE…).

This is available here: