pdf ("kuehl_16_01.pdf")

roughage <- read.fwf("C:\\data\\kuehl_16_01.dat", width=c(rep(8,10)),
col.names=c("sequence","trt","trt1","trt2","steer","period",
"carryover","carry1","carry2","digest"))

attach(roughage)

sequence <- factor(sequence)
trt <- factor(trt)
steer <- factor(steer)
period <- factor(period)
carryover <- factor(carryover)

digest.mod1 <- lm(digest ~ sequence + sequence/steer + period + trt + carryover)
anova(digest.mod1)

digest.mod2 <- lm(digest ~ sequence + sequence/steer + period + carryover + trt )
anova(digest.mod2)

digest.mod3 <- lm(digest ~ sequence + sequence/steer + period + trt1 + trt2 + carry1 + carry2)
summary(digest.mod3)
anova(digest.mod3)

digest.mod4 <- lm(digest ~ sequence + sequence/steer + period + carry1 + carry2 + trt1 + trt2)
summary(digest.mod4)
anova(digest.mod4)

dev.off()