| Variables | Standard error (P-value) of models | ||
| Pca | Stepwise regression | All variables | |
| X1 | - | 0.00000402 (0.0380) | 0.0000053 (0.018) |
| X2 | 0.04 (0.56) | - | 0.07 (0.24) |
| X3 | - | - | 0.04 (0.11) |
| X4 | 0.14 (0.35) | - | 0.16 (0.38) |
| X5 | 0.06 (0.80) | - | 0.06 (0.72) |
| X6 | 0.02 (0.00) | 0.02 (0.00) | 0.02 (0.01) |
| Count R2 | 0.70 | 0.63 | 0.53 |