The below lists the final weight (in grams) of 18 hamsters fed three different diets varying in fat content. The hamsters were blocked by weight in groups of three; that is, the hamsters in each block had the same weights at the start of the experiment. (a) Estimate the overall mean, the treatment means, and the block means. (b) Compare the three diets and test for differences among them by computing the ANOVA . Use α = 0.05. (c) Check the model assumptions by plotting the residuals.
(Source: J. L. Gill (1978), Design and Analysis of Experiments in the Animal and Medical Sciences, vol. 2, Iowa State University Press, Ames, IA. Used with permission.)