| Function name | Equation | Reference |
| Chi square statistic ( |
| [55] |
| Standard Deviation (SD) |
| [43] |
| Nash Coefficient of Efficiency (NSE) |
| [27] |
| Accuracy (Af) |
| [29] |
| Bias (Bf) |
| [29] |
| Relevance Factor (RF) |
| [43] |