I made these pages mostly to help myself remember things that took me a while to find explanations for, so I figured I might as well share them. All information presented has been synthesized from several statistics books, web sites and wikipedia. All formulas and text are my own work. Please let me know if there are any errors on any of the pages.

1. The standard error of the sample mean.

2. Why is the sample variance calculated over n-1 instead of n?