| covariate | Estimate | SE | P-Value |
| (Intercept) | 2.36746 | 0.33 | 0.06e-13*** |
| Z1 | 0.16405 | 0.33 | 0.619 |
| Z2 | −0.39876 | 0.33 | 0.229 |
| Z3 | 0.21046 | 0.35 | 0.551 |
| d | −0.10833 | 0.001 | <0.00001 |