Conover (1971, p. 326) presented data on the amount of iron found in the livers of white rats. Fifty rats were randomly divided into five groups of ten and each group was given a different diet. We analyze the logs of the original data. The total sample variance of the 50 observations is 0.521767 and the means for each diet are given below.

Diet A B C D E Mean 1.6517 0.87413 0.89390 0.40557 0.025882 Compute the analysis of variance table and test whether there are differences due to diet.

If diets A and B emphasize beef and pork, respectively, diet C emphasizes poultry, and diets D and E are based on dried beans and oats, the following contrasts may be of interest.

Diet Contrast A B C D E Beef vs. pork 1 −1 0 0 0 Mammals vs. poultry 1 1 −2 0 0 Beans vs. oats 0 0 0 1 −1 Animal vs. vegetable 2 2 2 −3 −3 Compute sums of squares for each contrast. Construct a hierarchy of models based on the diet labels and figure out how to test them using weighted least squares and the mean squared error for pure error that you found to construct the ANOVA table.What conclusions can you draw about the data?