Prediction of difference in swelling size between initial and final measurements at the avian tuberculin injection site (da) by ‘22’ genotype.

Incident risk and odds ratios for both components of a zero-inflated Poisson model fitted to the avian difference (da ∼ Age + a1 + p22). Odds and incident risk ratios (from the Poisson count model and binomial zero inflation terms respectively) are presented to two significant figures, along with 95% confidence intervals calculated from 10000 parametric bootstraps. Significant effects at the 95% level are highlighted in bold. While the age co-efficient is highly significant with the Poisson portion of the model, the p22 effect is only marginally significant for da. The marginal significance of the p22 effect is further emphasised by the variability in the bootstrapped confidence interval, which constitutes a more conservative test.