SD: (Weighted) 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, weights = NULL, na.rm = FALSE, ...)
Arguments
x
a numeric vector or an R object which is coercible to one
by as.double(x)
.
weights
a numerical vector of weights the same length as x
giving the weights to use for elements of x
.
na.rm
logical. Should missing values be removed?
…
further arguments passed to or from other methods.
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
.
See Also
var
for its square, and mad
, the most
robust alternative.