Table 2 Results of zero-truncated Poisson regression modelling for the offset-model (Model 1: offset is log-size of holding), for the model treating log-size as a free covariate (Model 2) and the model with a quadratic term included (Model 3) for the years 2002, 2003, and 2004 based upon the SND data. 
is the scrapie-affected population estimated by means of the generalized Horvitz-Thompson estimator and n the number of holdings confirmed with scrapie by the SND in each year.
is the scrapie-affected population estimated by means of the generalized Horvitz-Thompson estimator and n the number of holdings confirmed with scrapie by the SND in each year.From: On the question of proportionality of the count of observed Scrapie cases and the size of holding
α (S.E., 1Z) | β 1 | β 2 |
| log-likelihood (AIC, BIC) | |
|---|---|---|---|---|---|
2002 | (n = 144) | ||||
Model 1 | -4.3160 (0.0554, -77.92) | 1 (fixed) | - | 327 | -686.43 (1374.9, 1377.7) |
Model 2 | 0.8721 (0.1857, 4.70) | 0.0560 (0.0386, 3.43) | - | 151 | -431.81 (867.6, 873.3) |
Model 3 | -0.9608 (0.6344, -1.51) | 0.9498 (0.2768, 3.43) | -0.1002 (0.0298, -3.36) | 153 | -423.10 (852.2, 860.7) |
2003 | (n = 134) | ||||
Model 1 | -4.3845 (0.0571, -76.78) | 1 | - | 359 | -700.69 (1544.3, 1547.1) |
Model 2 | 1.2485 (0.1889, 6.61) | -0.0239 (0.0405, -0.59) | - | 139 | -399.90 (803.8, 809.4) |
Model 3 | -0.8759 (0.6186, -1.42) | 1.0482 (0.2841, 3.69) | -0.1252 (0.0324, -3.86) | 147 | -388.96 (783.9, 792.3) |
2004 | (n = 151) | ||||
Model 1 | -4.5671 (0.0653, -69.98) | 1 (fixed) | - | 363 | -439.16 (880.3, 883.2) |
Model 2 | 0.5373 (0.2810, 1.91) | 0.0566 (0.0573, 0.99) | 170 | -316.82 (637.6, 643.4) | |
Model 3 | -1.0624 (0.9407, -1.13) | 0.7776 (0.3953, 1.97) | -0.0773 (0.0412, -1.88) | 172 | -314.68 (635.3, 644.1) |