9.3 This question relates to the flu vaccine trial data in Table 9.6.

a. Using a conventional chi-squared test and an appropriate log-linear model, test the hypothesis that the distribution of responses is the same for the placebo and vaccine groups.

b. For the model corresponding to the hypothesis of homogeneity of response distributions, calculate the fitted values, the Pearson and deviance residuals, and the goodness of fit statistics X 2

and D. Which of the cells of the table contribute most to X 2

(or D)? Explain and interpret these results.