| Equation | Excluded | chi2 | df | Prob > chi2 |
| service | engel | 12.25 | 1 | 0.000 |
| service | ALL | 12.25 | 1 | 0.000 |
| engel | service | 12.66 | 1 | 0.000 |
| engel | ALL | 12.66 | 1 | 0.000 |