Rule No. | Range of k | Exponential equation | R2 value | SIF data set |
Rule #1 | 2 ≤ k ≤ 25 |
| R2 = 0.9579 | SIF2014 |
Rule #4 |
| R2 = 0.9705 | ||
Rule #5 |
| R2 = 0.9880 | ||
Rule #4 | 4 ≤ k ≤ 20 |
| R2 = 0.9915 | SIF2009 |
| R2 = 0.9842 | SIF2014 | ||
| R2 = 0.99 | SIF2015 | ||
Rule #5 | 4 ≤ k ≤ 20 |
| R2 = 0.9915 | SIF2009 |
| R2 = 0.9951 | SIF2014 | ||
| R2 = 0.9952 | SIF2015 |