Refer to Problem 6.6 with Table 6.13.

a. Fit model (AD, AG, DG). Using the fitted values, estimate the A-G condi- tional odds ratio and the A-G marginal odds ratio. Explain why they give different indications of the A-G association.

b. Is it proper to use G((AD, DG) | (AD, AG, DG)] to test conditional inde- pendence of A and G? Explain.

c. From Problem 6.6, the adjusted residuals for model (AD,DG) suggest that Department 1 differs from the others. Using only Departments 2 through 6, fit models (AD, DG) and (AD, AG, DG) and test A-G conditional indepen- dence. Interpret.

d. Explain how results in (a)-

(c) apply to corresponding logit models, with A as the response.