Samples of six different brands of diet/imitation margarine were analyzed to determine the level of physiologically active polyunsaturated fatty acids (PAPFUA, in percentages), resulting in the following data:

Imperial 14.1 13.6 14.4 14.3 Parkay 12.8 12.5 13.4 13.0 12.3 Blue Bonnet 13.5 13.4 14.1 14.3 Chiffon 13.2 12.7 12.6 13.9 Mazola 16.8 17.2 16.4 17.3 18.0 Fleischmann’s 18.1 17.2 18.7 18.4

(The preceding numbers are fictitious, but the sample means agree with data reported in the January 1975 issue of Consumer Reports.)

a. Use ANOVA to test for differences among the true average PAPFUA percentages for the different brands.

b. Compute CIs for all .

c. Mazola and Fleischmann’s are corn-based, whereas the others are soybean-based. Compute a CI for

[Hint: Modify the expression for that led to (10.5) in the previous section.]