Analysis of Variance: Weight Gain, Foster Feeding in Rats, Water Hardness and Male Egyptian Skulls

The data in Table 5.1 (from Hand et al., 1994) arise from an experiment to study the gain in weight of rats fed on four different diets, distinguished by amount of protein (low and high) and by source of protein (beef and cereal). Ten rats are randomised to each of the four treatments and the weight gain in grams recorded. The question of interest is how diet affects weight gain.