Semi2 {SASmixed}R Documentation

Oxide layer thicknesses on semiconductors

Description

The Semi2 data frame has 72 rows and 5 columns.

Format

This data frame contains the following columns:

Source
a factor with levels 1 and 2
Lot
a factor with levels 1 to 8
Wafer
a factor with levels 1 to 3
Site
a factor with levels 1 to 3
Thickness
a numeric vector

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 4.4).

Examples

library(SASmixed)
options(
  contrasts = c(unordered = "contr.SAS", ordered = "contr.poly"))
data(Semi2)
formula(Semi2)
fm1Semi2 <- lme( Thickness ~ 1, data = Semi2,
   random = ~ 1 | Lot/Wafer )
summary( fm1Semi2 )       # compare with output 4.13, p. 156
VarCorr( fm1Semi2 )
anova( fm1Semi2 )
fm2Semi2 <- update( fm1Semi2, Thickness ~ Source )
summary( fm2Semi2 )       # compare with output 4.15, p. 159
VarCorr( fm2Semi2 )
fm3Semi2 <- update( fm2Semi2, 
   random = list(Lot = pdDiag( ~ Source - 1 ), Wafer = ~ 1 ) )
summary( fm3Semi2 )       # compare with output 4.17, p. 163
VarCorr( fm3Semi2 )