15.11. A sample of inmates being admitted to the Rhode Island Department of Corrections were asked whether they ever injected drugs and were tested for hepatitis C virus (HCV). The numbers who reported injecting drugs were 306 of the 887 men who tested HCV positive, 61 of the 3044 men who tested HCV negative, 110 of the 197 women who tested HCV positive, and 13 of the 288 women who tested HCV negative. The authors9 concluded that the prevalence of HCV may be underestimated by testing only those who reported injecting drugs.

(a) Report the results as a contingency table.

(b) Define dummy variables and specify a model for which the odds ratios between HCV status and whether injected drugs are identical in the population for each sex.

(c) Fit the model in (b), and report the model-based estimate of the odds ratio in (b).