robustbase (version 0.5-0-1)

SiegelsEx: Siegel's Exact Fit Example Data

Description

A small counterexample data set devised by Andrew Siegel. Six (out of nine) data points lie on the line $y = 0$ such that some robust regression estimators exhibit the exact fit property.

Usage

data(SiegelsEx)

source

Emerson and Hoaglin (1983, p.139)

References

Peter J. Rousseeuw and Annick M. Leroy (1987) Robust Regression and Outlier Detection Wiley, p.60--61

Examples

data(SiegelsEx)
plot(SiegelsEx, main = "Siegel's example for 'exact fit'")
abline(          lm(y ~ x, data = SiegelsEx))
abline(MASS::lqs(y ~ x, data = SiegelsEx, method = "lms"), col = 2)
legend("topright", leg = c("lm", "LMS"), col=1:2, lwd=1, inset = 1/20)