hormone <- read.table("http://www.stat.ufl.edu/~winner/sta4211/datasets/CH23TA02.txt",header=F, col.names=c("i", "j", "k","growrate","X1", "X2", "X3","X1X2","X1X3")) attach(hormone) hormone.reg1 <- lm(growrate ~ X1 + X2 + X3 + X1X2 + X1X3) summary(hormone.reg1) anova(hormone.reg1) drop1(hormone.reg1) hormone.reg2 <- lm(growrate ~ X1 + X2 + X3) summary(hormone.reg2) anova(hormone.reg2) drop1(hormone.reg2) hormone.reg3 <- lm(growrate ~ X2 + X3 + X1X2 + X1X3) summary(hormone.reg3) anova(hormone.reg3) drop1(hormone.reg3) hormone.reg4 <- lm(growrate ~ X1 + X1X2 + X1X3) summary(hormone.reg4) anova(hormone.reg4) drop1(hormone.reg4) anova(hormone.reg2,hormone.reg1) anova(hormone.reg3,hormone.reg1) anova(hormone.reg4,hormone.reg1)