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. Earlier versions of R allowed matrices or data frames forx, see below. - 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 NAs if na.rm = TRUE) is not defined and gives an error. The standard deviation of a length-one vector is NA.
In earlier versions R, for a data.frame dfrm, sd(dfrm) worked directly. This is deprecated now, and you are expected to use sapply(dfrm, sd) instead.
Examples
sd(1:2) ^ 2
Documentation reproduced from R 2.15.0. License: GPL-2.