Excel's STDEV formula can automatically calculate the standard deviation of any set of numbers, so you don't have to go through the math yourself.

Learn how to calculate Standard Deviationin Excel. The STDEV function can be used to estimate standard deviation based on sample in Excel.

Because risk means different things to different people, there's no perfect way to measure risk. But through decades of mostly academic research, investors have largely settled on standard deviation.

For example, if Mutual Fund A has an average annual return of 10% and a standard deviation of 4%, you would expect about 68% of the time for the return to be between 6% and 14% (1 standard ...

For example, if you're measuring the average diameter of precision part you are manufacturing for a customer, a small standard deviation means your production process is producing consistent products.

To answer that, I found the standard deviation of 55 players—15 quarterbacks, and 20 of both running backs and wide receivers—each the best at their positions (according to ESPN's rankings).

The equation for the standard error of the mean is the sample standard deviation divided by the square root of the sample size.