# std

## Purpose

Standard deviation.

## Synopsis

    s = std(X)

## Description

`s = std(X)`, where `X` is a matrix, returns a row vector `s` containing the standard deviation of each column.If `X` is a vector, `s` is the standard deviation of the elements of `X`.

The standard deviation `s` of a sample of data is

where

and n is the number of elements in the sample.

Using this definition, `s.^2` is the minimum variance unbiased estimate of sigma squared (the scale parameter of the normal distribution).

## See Also

    corrcoef, cov, mean, median

(c) Copyright 1994 by The MathWorks, Inc.