chicks.dat <- read.table("chicks.dat", header=TRUE)

par(mfrow=c(2,1))
plot.design(chicks.dat)
plot.design(chicks.dat, fun=median)

attach(chicks.dat)

par(mfrow=c(2,2))
 
boxplot(Weight ~ Protein)
boxplot(Weight ~ LP)
boxplot(Weight ~ LS)
boxplot(Weight ~ House)

chicks.aov <- aov(Weight ~ Protein*LP*LS*House)

summary(chicks.aov)

interaction.plot(Protein,House,Weight)
interaction.plot(LP,House,Weight)
interaction.plot(LS,House,Weight)

interaction.plot(LP,Protein,Weight)

## could also include tables for mean weights by group,
## anova table, etc.