robustloggamma (version 1.0-2.1)

alcoa: Quality assurance measurement on aluminium.

Description

Three samples (with labels A,B and C) from measurement quality assurance (QA) data base of ALCOA aluminium refineries in Western Australia.

Usage

data(alcoa)

Format

A data frame with 668 observations on the following 3 variables.

dist

a numeric vector

ratio

a numeric vector

label

a factor with levels A B C

Details

Under ALCOA's QA program, several thousand bauxite ore samples are routinely submitted to Fourier transform infrared spectroscopy (Eyer and Riley, 1999). Part of the quality assurance is the need to automatically highlight unusual spectra and this is obtained with the help of special statistical diagnostics - called representation indicators - derived from the Fourier transform.

References

C. Agostinelli, A. Marazzi and V.J. Yohai (2015). Robust estimates of the generalized loggamma distribution. Technometrics, Volume 56, Issue 1, 2014. doi:10.1080/00401706.2013.818578

Clarke B.R., McKinnon P.L., Riley G. (2012). A fast robust method for fitting gamma distributions. Statistical Papers, 53, 4, 1001-1014.

Eyer S., Riley G. (1999). Measurement quality assurance in a production system for bauxite analysis by FTIR. North American Chapter of the International Chemometrics Society, Newsl No. 19.

Examples

# NOT RUN {
data(alcoa)
par(mfcol=c(1,2))
boxplot(I(log(alcoa$ratio))~alcoa$label)
boxplot(I(log(alcoa$dist))~alcoa$label)
# }