Table 4.
Mean estimated parameters (mean asymptotic variance, simulation variance) and the coverage probabilities (CP) (%) over 1000 realizations for the ZIP response when the Main Model is misspecified. The variances are in 10—2 for czp, a0,b0 and b1, 10—1 for the other estimates except for c0b
| The estimates of the parameters for the poisson component of the Main Model: | ||||||||
| c0p = 1 | cxp = 1 | czp = 1 | ||||||
| N | Est. | CP | Est. | CP | Est. | CP | ||
| 200 | −0.214 ( 0.38 0.47 ) | 4.3 | 0.609 ( 0.38 0.70 ) | 29.5 | 0.969 ( 2.46 3.35 ) | 90.6 | ||
| 500 | −0.211 ( 0.14 0.16 ) | 0.0 | 0.676 ( 0.08 0.17 ) | 2.9 | 0.947 ( 0.82 1.15 ) | 85.0 | ||
| fOOO | −0.210 ( 0.07 0.09 ) | 0.0 | 0.699 ( 0.03 0.08 ) | 0.1 | 0.946 ( 0.38 0.58 ) | 78.1 | ||
| The estimates of the parameters for the zero-inflated component of the Main Model: | ||||||||
| c0p = −1 | cxb = 1 | czp = 1 | ||||||
| N | Est. | CP | Est. | CP | Est. | CP | ||
| 200 | −0.230 ( 0.24 0.26 ) | 52.0 | 0.730 ( 1.67 1.36 ) | 79.4 | 1.038 ( 2.07 2.47 ) | 92.5 | ||
| 500 | −0.162 ( 0.08 0.07 ) | 16.9 | 0.704 ( 0.33 0.24 ) | 56.7 | 0.945 ( 0.63 0.67 ) | 92.7 | ||
| 1000 | −0.149 ( 0.04 0.04 ) | 1.9 | 0.701 ( 0.16 0.11 ) | 33.2 | 0.916 ( 0.30 0.30 ) | 90.1 | ||
| The estimates of the parameters for the Auxiliary Model: | ||||||||
| a0 = 0.5 | a1 = 1 | b0 = 0.5 | b1 = l | |||||
| N | Est. | CP | Est. | CP | Est. | CP | Est. | CP |
| 200 | 0.468 ( 7.33 7.47 ) | 94.9 | 1.095 ( 13.70 1.60 ) | 94.3 | 0.486 ( 1.75 1.82 ) | 95.1 | 1.013 ( 1.86 1.92 ) | 93.9 |
| 500 | 0.488 ( 2.72 2.74 ) | 95.3 | 1.036 ( 4.80 0.40 ) | 96.6 | 0.493 ( 0.68 0.68 ) | 95.5 | 1.003 ( 0.66 0.61 ) | 96.6 |
| 1000 | 0.493 ( 1.33 1.42 ) | 93.7 | 1.025 ( 2.30 0.30 ) | 93.5 | 0.498 ( 0.34 0.33 ) | 94.8 | 0.998 ( 0.32 0.35 ) | 94.1 |