Calculates a non-parametric version of the coefficient of
variation where the standard deviation is replaced by the median
absolute deviations (see `mad`

for details) and
divided by the absolute value of the mean.

## Arguments

- x
A `numeric`

.

- na.rm
A `logical`

(default is `TRUE`

indicating
whether `NA`

values should be stripped before the computation
of the median absolute deviation and mean.

## Details

Note that the `mad`

of a single value is 0 (as opposed to
`NA`

for the standard deviation, see example below).

## Examples

```
set.seed(1)
npcv(rnorm(10))
#> [1] 5.852407
replicate(10, npcv(rnorm(10)))
#> [1] 3.112625 6.088948 4.928480 5.534139 6.124995 2.354319 2.996464
#> [8] 6.049891 11.716089 3.265193
npcv(1)
#> [1] 0
mad(1)
#> [1] 0
sd(1)
#> [1] NA
```