weighted.mean
Weighted Arithmetic Mean
Compute a weighted mean.
 Keywords
 univar
Usage
weighted.mean(x, w, ...)
"weighted.mean"(x, w, ..., na.rm = FALSE)
Arguments
 x
 an object containing the values whose weighted mean is to be computed.
 w
 a numerical vector of weights the same length as
x
giving the weights to use for elements ofx
.  ...
 arguments to be passed to or from methods.
 na.rm
 a logical value indicating whether
NA
values inx
should be stripped before the computation proceeds.
Details
This is a generic function and methods can be defined for the first
argument x
: apart from the default methods there are methods
for the datetime classes "POSIXct"
, "POSIXlt"
,
"difftime"
and "Date"
. The default method will work for
any numericlike object for which [
, multiplication, division
and sum
have suitable methods, including complex vectors.
If w
is missing then all elements of x
are given the
same weight, otherwise the weights coerced to numeric by
as.numeric
and normalized to sum to one (if possible: if
their sum is zero or infinite the value is likely to be NaN
).
Missing values in w
are not handled specially and so give a
missing value as the result. However, zero weights are handled
specially and the corresponding x
values are omitted from the
sum.
Value

For the default method, a lengthone numeric vector.
See Also
Examples
library(stats)
## GPA from Siegel 1994
wt < c(5, 5, 4, 1)/15
x < c(3.7,3.3,3.5,2.8)
xm < weighted.mean(x, wt)