gmd() computes Gini's mean difference for a numeric vector or for all numeric vectors in a data frame.

gmd(x, ...)

Arguments

x

A vector or data frame.

...

Optional, unquoted names of variables that should be selected for further processing. Required, if x is a data frame (and no vector) and only selected variables from x should be processed. You may also use functions like : or tidyselect's select_helpers().

Value

For numeric vectors, Gini's mean difference. For non-numeric vectors or vectors of length < 2, returns NA.

Note

Gini's mean difference is defined as the mean absolute difference between any two distinct elements of a vector. Missing values from x are silently removed.

References

David HA. Gini's mean difference rediscovered. Biometrika 1968(55): 573-575

Examples

data(efc)
gmd(efc$e17age)
#> [1] 9.297005
gmd(efc, e17age, c160age, c12hour)
#> # A tibble: 1 x 3
#>   e17age c160age c12hour
#>    <dbl>   <dbl>   <dbl>
#> 1   9.30    15.2    47.9