Sample or population?
Use the sample standard deviation (divides by n − 1) when your numbers are part of a larger group, like a survey. Use the population one (divides by n) when you have every value of the group.
Example
7, 8.5, 6, 9, 10, 7.5 and 8: mean 8, median 8, sample standard deviation about 1.32.
Frequently asked questions
What does the standard deviation tell me?
How spread out the numbers are around the mean. A small value means they are close to the average.
See also
Results are estimates for information only and are not financial, legal or medical advice. Rates, taxes and fees vary — confirm with a professional or your lender.