| Dummy variables | Significant level 5% | Significant level 10% | ||||
| No. of significant | No. of significant and positive | No. of significant and negative | No. of significant | No. of significant and positive | No. of significant and negative | |
| b1 | 68 | 5 | 63 | 79 | 6 | 73 |
| b2 | 42 | 19 | 23 | 60 | 30 | 30 |
| b3 | 48 | 13 | 35 | 71 | 20 | 51 |
| Total | 158 | 37 | 121 | 210 | 56 | 154 |