# sd {stats}

### Description

This function computes the standard deviation of the values in `x`

. If `na.rm`

is `TRUE`

then missing values are removed before computation proceeds.

### Usage

sd(x, na.rm = FALSE)

### Arguments

- x
- a numeric vector or an R object which is coercible to one by
`as.vector(x, "numeric")`

. - na.rm
- logical. Should missing values be removed?

### Details

Like `var`

this uses denominator n - 1.

The standard deviation of a zero-length vector (after removal of `NA`

s if `na.rm = TRUE`

) is not defined and gives an error. The standard deviation of a length-one vector is `NA`

.

Prior to R 2.14.0, `sd(dfrm)`

worked directly for a data.frame `dfrm`

. This is now defunct and you are expected to use `sapply(dfrm, sd)`

.

### Examples

sd(1:2) ^ 2

Documentation reproduced from R 3.0.2. License: GPL-2.