matrixStats (version 0.14.0)

weightedMean: Weighted Arithmetic Mean

Description

Computes the weighted sample mean of a numeric vector.

Usage

weightedMean(x, w, na.rm=FALSE, refine=FALSE, ...)

Arguments

x

a numeric vector containing the values whose weighted 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. Negative weights are treated as zero weights. Default value is equal weight to all values.

na.rm

a logical value indicating whether NA values in x should be stripped before the computation proceeds, or not. If NA, no che

refine

If TRUE and x is numeric, then extra effort is used to calculate the average with greater numerical precision, otherwise

...

Not used.

Value

• Returns a numeric scalar.

encoding

latin1

See Also

mean() and weighted.mean.

Examples

x <- 1:10
n <- length(x)

w <- rep(1, times=n)
m0 <- weighted.mean(x, w)
m1 <- weightedMean(x, w)
stopifnot(identical(m1,m0))

# Pull the mean towards zero
w[1] <- 5
m0 <- weighted.mean(x, w)
m1 <- weightedMean(x, w)
stopifnot(identical(m1,m0))

# Put even more weight on the zero
w[1] <- 8.5
m0 <- weighted.mean(x, w)
m1 <- weightedMean(x, w)
stopifnot(identical(m1,m0))

# All weight on the first value
w[1] <- Inf
m0 <- weighted.mean(x, w)
m1 <- weightedMean(x, w)
stopifnot(identical(m1,m0))

# All weight on the last value
w[1] <- 1
w[n] <- Inf
m0 <- weighted.mean(x, w)
m1 <- weightedMean(x, w)
stopifnot(identical(m1,m0))

# All weights set to zero
w <- rep(0, n)
m0 <- weighted.mean(x, w)
m1 <- weightedMean(x, w)
stopifnot(identical(m1,m0))