| sd {stats} | R Documentation |
Standard Deviation
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 |
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.
See Also
var for its square, and mad, the most
robust alternative.
Examples
sd(1:2) ^ 2