gx.ngr.skew: Estimate the Skewness of a Data Vector

In rgr: Applied Geochemistry EDA

Description

Estimates the skew of a data vector for gx.ngr.stats to be used by gx.ngr.summary to output a NGR Table of summary statistics as a ‘.csv’ file.

Usage

gx.ngr.skew(xx)

Arguments

xx	vector for which the skewness is required.

Details

The formula used, (m3 / m2^1.5) * ((n-1)/n)^1.5, where m3 and m2 are the third and second moments about the mean, respectively, provides an estimate similar to that obtained by Minitab and BMDP.

Value

skew	the estimate of the skewness of the data vector passed to the function.

Note

Any less than detection limit values represented by negative values, or zeros or other numeric codes representing blanks in the data, must be removed prior to executing this function, see ltdl.fix.df.

Any NAs in the data vector will be removed prior to computation.

Author(s)

Robert G. Garrett

Examples

## Make test data available
data(sind)
attach(sind)

## Estimate and display the skewness of the Zn data 
skew <- gx.ngr.skew(Zn)
skew

## Alternately
skew <- gx.ngr.skew(rnorm(0,1,1000))
skew

## Detach test data
detach(sind)

rgr documentation built on May 2, 2019, 6:09 a.m.