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
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)
.
var
for its square, and mad
, the most
robust alternative.
sd(1:2) ^ 2