(Robust) Range

Determines the range of the data, which can possibly be trimmed before calculating the extreme values. The robust range version is calculated on the basis of the trimmed mean and variance (see Details).

Usage

rangeX(x, trim = NULL, robust = FALSE, na.rm = FALSE, ...)

Arguments

x

a numeric vector

trim

the fraction (0 to 0.5) of observations to be trimmed from each end of x before the range is computed. Values of trim outside that range are taken as the nearest endpoint. Default is 0 for robust = FALSE and 0.2 for robust = TRUE.

robust

logical; whether to return the robust or conventional range

na.rm

a logical value indicating whether NA values should be stripped before the computation proceeds

...

further arguments passed to .robRange, including fac. Only used if robust = TRUE.

Value

a numeric scalar containing the range width. The corresponding lower and upper bounds are returned in the "bounds" attribute. Note that the attribute is dropped by subsetting and by as.vector(), so read it before computing on the result.

Details

The R base function range returns the minimum and maximum value of a numeric object. Here we return the span of a (possibly trimmed) numeric vector, say the difference of maximum and minimum value.

If robust is set to TRUE the function determines the trimmed mean m and then the "upper trimmed mean" s of absolute deviations from m, multiplied by fac (fac is 3 by default). The robust minimum is then defined as m-fac*s or min(x), whichever is larger, and similarly for the maximum.

Note

Robust range contributed by Werner Stahel.

See also

range(), min(), max()

Other dispersion: coefVar(), iqrX(), madX(), meanAD(), meanSE(), varX()

Examples

x <- c(0:10, 50)
xm <- rangeX(x)
c(xm, rangeX(x, trim = 0.10))
#> [1] 50  9

x <- c(rnorm(20), rnorm(3, 5, 20))
rangeX(x, robust=TRUE)
#> [1] 3.546073
#> attr(,"bounds")
#> [1] -1.539950  2.006123

# compared to
rangeX(x)
#> [1] 22.62374
#> attr(,"bounds")
#> [1] -1.53995 21.08379