stats (version 3.6.2)

# weighted.mean: Weighted Arithmetic Mean

## Description

Compute a weighted mean.

## Usage

```weighted.mean(x, w, …)# S3 method for default
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 of `x`.

arguments to be passed to or from methods.

na.rm

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

## Value

For the default method, a length-one numeric vector.

## 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 date-time classes `"POSIXct"`, `"POSIXlt"`, `"difftime"` and `"Date"`. The default method will work for any numeric-like 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.

`mean`

## Examples

Run this code
``````# NOT RUN {
## 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)
# }
``````

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