A data frame with 30 observations on the following 4 variables.
Protein
levels of protein (x 10) found in rat livers
Treatment
a factor with levels "Control",
"CPFA50", "CPFA150", "CPFA300",
"CPFA450" and "CPFA600"
Day
a factor with levels "Day1", "Day2",
"Day3", "Day4" and "Day5"
Group
a factor with levels "Group1",
"Group2", ..., "Group10"; the observed levels of the
Treatment and Day interaction