5.8. Table 5.8 summarizes observations of passengers in autos and light trucks involved in accidents in Maine in one year. The table classifies passengers TABLE 5.8. Passenger Observations Gender Female Male Location Urban Rural Urban Rural Seat Belt Use No Yes No Yes No Yes No Yes 1

7,287 11,587 3,246 6,134 10,381 10,969 6,123 6,693 Extent of Injury"

2 175 126 73 94 136 83 141 74 3

720 577 710 564 566 259 710 353 4

91 48 159 82 96 37 188 74 5

10 8

31 17 14 1

45 12

(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.