weighted.mean              package:base              R Documentation

Weighted Arithmetic Mean

Description:

     Compute a weighted mean of a numeric vector.

Usage:

     weighted.mean(x, w, na.rm=FALSE)

Arguments:

       x: a numeric vector containing the values whose mean is to be
          computed.

       w: a vector of weights the same length as `x' giving the weights
          to use for each element of `x'.

   na.rm: a logical value indicating whether `NA' values in `x' should
          be stripped before the computation proceeds.

Details:

     If `w' is missing then all elements of `x' are given the same
     weight.

     Missing values in `w' are not handled.

See Also:

     `mean'

Examples:

     ## 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)

