Somewhere back in your middle school and high school math classes, you no doubt learned about the mean and standard deviation as fairly fundamental concepts in arithmetic and statistics. You also knew ...

When reviewing cash flow data for your small business, knowing the standard deviation can help you determine if the numbers are out of whack. Calculating standard deviation manually can be ...

There are two formulae for standard deviation. \(s = \sqrt {\frac{{\sum {{{(X - \bar X)}^2}} }}{{n - 1}}}\) (where n is the sample size). The second formula is a re ...

In response to my article, Is the Stock Market Too Concentrated?, which relied upon standard-deviation calculations to assess investment risk, a reader wrote: “My problem [with your argument] is ...