| sd {stats} | R Documentation |
This function computes the standard deviation of the values in
x.
If na.rm is TRUE then missing values are removed before
computation proceeds.
sd(x, na.rm = FALSE)
x |
a numeric vector or an R object which is coercible to one
by |
na.rm |
logical. Should missing values be removed? |
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.
var for its square, and mad, the most
robust alternative.
sd(1:2) ^ 2