robustbase: hbk – R documentation

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hbk

Hawkins, Bradu, Kass's Artificial Data

Description

Artificial Data Set generated by Hawkins, Bradu, and Kass (1984). The data set consists of 75 observations in four dimensions (one response and three explanatory variables). It provides a good example of the masking effect. The first 14 observations are outliers, created in two groups: 1–10 and 11–14. Only observations 12, 13 and 14 appear as outliers when using classical methods, but can be easily unmasked using robust distances computed by, e.g., MCD - covMcd().

Usage

data(hbk, package="robustbase")

Format

A data frame with 75 observations on 4 variables, where the last variable is the dependent one.

X1: x[,1]
X2: x[,2]
X3: x[,3]
Y: y

Note

This data set is also available in package wle as artificial.

Source

Hawkins, D.M., Bradu, D., and Kass, G.V. (1984) Location of several outliers in multiple regression data using elemental sets. Technometrics 26, 197–208.

P. J. Rousseeuw and A. M. Leroy (1987) Robust Regression and Outlier Detection; Wiley, p.94.

Examples

data(hbk)
plot(hbk)
summary(lm.hbk <- lm(Y ~ ., data = hbk))

hbk.x <- data.matrix(hbk[, 1:3])
(cHBK <- covMcd(hbk.x))

robustbase

Basic Robust Statistics

v0.93-7

GPL (>= 2)

Authors

Martin Maechler [aut, cre] (<https://orcid.org/0000-0002-8685-9910>), Peter Rousseeuw [ctb] (Qn and Sn), Christophe Croux [ctb] (Qn and Sn), Valentin Todorov [aut] (most robust Cov), Andreas Ruckstuhl [aut] (nlrob, anova, glmrob), Matias Salibian-Barrera [aut] (lmrob orig.), Tobias Verbeke [ctb, fnd] (mc, adjbox), Manuel Koller [aut] (mc, lmrob, psi-func.), Eduardo L. T. Conceicao [aut] (MM-, tau-, CM-, and MTL- nlrob), Maria Anna di Palma [ctb] (initial version of Comedian)

Initial release

2021-01-04

hbk