Data from a foster feeding experiment with rat mothers and litters of
four different genotypes:
Rat litters were separated from their natural mothers at birth and
given to foster mothers to rear.
The data frame has the following components:
- genotype of the litter.
- genotype of the foster mother.
- Litter average weight gain of the litter, in grams at age 28 days. (The source states that the within-litter variability is negligible.)
Venables, W. N. and Ripley, B. D. (1999) Modern Applied Statistics with S-PLUS. Third Edition. Springer.