# Reference/sdev

## sdev (statistical standard deviation function)

Computes the statistical standard deviation of a list (as the square root of the statistical variance).

$sdev(x)=\sqrt{\frac{n}{n-1}var(x)}$

sdev applies to all numeric data types and throws an error with temporal types, char and sym.

## Syntax

q)r:sdev X


## Example

q)sdev 10 343 232 55
155.1322
q)select sdev price by sym from trade


For a complete list of functions, see the kdb+ Function Reference.