5.4. A cumulative link row effects model for an r x c contingency table with a qualitative predictor is h[P(Y

(a) Show that the residual df = (r - l)(c - 2).

(b) When this model holds, explain why independence corresponds to x\ =    = xr and the test of independence has df = r — 1.

(c) When this model holds, explain why the rows are stochastically ordered on Y.