Table 8.
Negative binomial regression parameter estimation.
| Parameter | Estimate | Std. dev. | 95% LCL | 95% UCL | p-Value |
|---|---|---|---|---|---|
| Intercept | −3.94 | 0.49 | −4.91 | −2.98 | <0.001 |
| Exposure (Hours Driven) | 1.20 | 0.14 | 0.92 | 1.48 | <0.001 |
| Cluster 1 vs. 4 | 0.22 | 0.17 | −0.11 | 0.55 | 0.187 |
| Cluster 2 vs. 4 | 0.48 | 0.24 | 0.01 | 0.95 | 0.044* |
| Cluster 3 vs. 4 | −0.10 | 0.13 | −0.36 | 0.16 | 0.465 |
| Years of commercial vehicle driving | −0.02 | 0.01 | −0.03 | −0.01 | 0.010* |
| Age | 0.00 | 0.01 | −0.01 | 0.01 | 0.644 |
| Gender (M vs. F) | 0.69 | 0.25 | 0.19 | 1.18 | 0.007* |
| BMI | 0.03 | 0.01 | 0.01 | 0.04 | 0.005* |
| Dispersion | 3.23 | 0.23 | 2.81 | 3.72 | |
| Chi-square/DF | 1.43 | ||||
| Deviance/DF | 0.75 |
*
Indicates the p-value < 0.05.