Modified Data on Wood Specific Gravity

Description

The original data are from Draper and Smith (1966) and were used to determine the influence of anatomical factors on wood specific gravity, with five explanatory variables and an intercept. These data were contaminated by replacing a few observations with outliers.

Usage

data(wood)

Format

A data frame with 20 observations on the following 6 variables.

x1, x2, x3, x4, x5

explanatory “anatomical” wood variables.

y

wood specific gravity, the target variable.

Source

Draper and Smith (1966, p.227)

Peter J. Rousseeuw and Annick M. Leroy (1987) Robust Regression and Outlier Detection Wiley, p.243, table 8.

Examples

data(wood)
plot(wood)
summary( lm.wood <-        lm(y ~ ., data = wood))
summary(rlm.wood <- MASS::rlm(y ~ ., data = wood))
summary(lts.wood <-    ltsReg(y ~ ., data = wood))

wood.x <- as.matrix(wood)[,1:5]
c_wood <- covMcd(wood.x)
c_wood