mean                  package:base                  R Documentation

Arithmetic Mean

Description:

     Generic function for the (trimmed) arithmetic mean.

Usage:

     mean(x, ...)
     mean.default(x, trim = 0, na.rm = FALSE, ...)

Arguments:

       x: An R object.  Currently there are methods for numeric data
          frames, numeric vectors and dates.  A complex vector is
          allowed for `trim = 0', only.

    trim: the fraction (0 to 0.5) of observations to be trimmed from
          each end of `x' before the mean is computed.

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

     ...: further arguments passed to or from other methods.

Value:

     For a data frame, a named vector with the appropriate method being
     applied column by column.

     If `trim' is zero (the default), the arithmetic mean of the values
     in `x' is computed.

     If `trim' is non-zero, a symmetrically trimmed mean is computed
     with a fraction of `trim' observations deleted from each end
     before the mean is computed.

See Also:

     `weighted.mean', `mean.POSIXct'

Examples:

     x <- c(0:10, 50)
     xm <- mean(x)
     c(xm, mean(x, trim = 0.10))

     all.equal(mean(x, trim = 0.5), median(x))

     data(USArrests)
     mean(USArrests, trim = 0.2)

