15.19. Refer to the 3×7 table in Table 12.1 (page 364) on party identification and political ideology.

(a) Fit a baseline-category logit model, treating party affiliation as the response and political ideology as a quantitative explanatory variable. Interpret the political ideology effect for the choice between Democrat and Republican.

(b) Fit a cumulative logit model, treating political ideology as the response. Interpret the cumulative odds ratio for comparing Democrats and Republicans on ideology.