The data are from a foster feeding experiment with rat mothers and litters of four different genotypes. The measurement is the litter weight after a trial feeding period.
A data frame with 61 observations on the following 3 variables.
genotype of the litter, a factor with levels
genotype of the mother, a factor with levels
the weight of the litter after a feeding period.
Here the interest lies in uncovering the effect of genotype of mother and litter on litter weight.
D. J. Hand, F. Daly, A. D. Lunn, K. J. McConway and E. Ostrowski (1994). A Handbook of Small Datasets, Chapman and Hall/CRC, London.
data("foster", package = "HSAUR") plot.design(foster)