| Var | ind | CO2 |
| 第一阶段 | 第二阶段 | |
| ind |
| 0.8946*** |
|
| (0.1224) | |
| IV_ind | 0.9387*** |
|
| (0.0246) |
| |
| Control | 控制 | 控制 |
| Underidentification test | 800.5780 | 702.0710 |
| Weak identification test | 408.1080 | 457.4430 |