pdf("woolfrict.pdf")

wf1 <- read.fwf("http://www.stat.ufl.edu/~winner/data/woolfrict1.dat",
width=c(8,8,8,8),
col.names=c("runnum", "trt", "revs", "shrink"))

attach(wf1)

trt <- factor(trt, levels=1:4,
labels=c("Untreated", "AC15sec", "AC4min", "AC15min"))

runnum <- factor(runnum, levels=1:4) 
revs <- factor(revs,levels=seq(200,1400,200),ordered=TRUE)

# Fit full ANOVA with all terms, F-test for trt is inappropriate
woolfrict.sp1 <- aov(shrink ~ trt + runnum + trt:runnum + revs + revs:trt)
summary(woolfrict.sp1)

# This model uses correct error terms for trt and revs and interaction
woolfrict.sp2 <- aov(shrink ~ trt*revs + Error(runnum/trt))
summary(woolfrict.sp2)

# Partitions the Revs SS into orthogonal polynomials 
summary(woolfrict.sp2,split=list(revs=list(linear=1, quadratic=2,
cubic=3, quartic=4, quintic=5, sextic=6)))

dev.off()