[Glossary](https://useratio.app/glossary) › Maths and statistics

# Standard deviation

A measure of how spread out a set of numbers is around their mean.

A small value means the numbers sit close to the mean; a large one means they are scattered. Ratio gives the sample standard deviation, which divides by one less than the number of values.

## In Ratio

| You type | Ratio shows |
| --- | --- |
| `stdev(2, 4, 4, 4, 5, 5, 7, 9)` | 2.1381 |

## Related

[Median and mean](https://useratio.app/glossary/median) · [All terms](https://useratio.app/glossary)

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Source: https://useratio.app/glossary/standard-deviation