Semiconductor split-plot experiment

Description

The Semiconductor data frame has 48 rows and 5 columns.

Format

This data frame contains the following columns:

resistance

a numeric vector

ET

a factor with levels 1 to 4 representing etch time.

Wafer

a factor with levels 1 to 3

position

a factor with levels 1 to 4

Grp

an ordered factor with levels 1/1 < 1/2 < 1/3 < 2/1 < 2/2 < 2/3 < 3/1 < 3/2 < 3/3 < 4/1 < 4/2 < 4/3

Details

Source

Littel, R. C., Milliken, G. A., Stroup, W. W., and Wolfinger, R. D. (1996), SAS System for Mixed Models, SAS Institute (Data Set 2.2(b)).

Examples

library(SASmixed)
options(
  contrasts = c(unordered = "contr.SAS", ordered = "contr.poly"))
data(Semiconductor)
formula( Semiconductor )
names( Semiconductor )
fm1Semi <- lme( resistance ~ ET * position,
                 data = Semiconductor,
                 random = ~ 1 | Grp)
summary( fm1Semi )
VarCorr( fm1Semi )
anova( fm1Semi )
fm2Semi <- update( fm1Semi, resistance ~ ET + position )
anova(fm2Semi)