Parameters of the designed model.
| Source | Sum of squares | Degree of freedom (df) | Mean square (MS) | F-value | p-value |
|---|---|---|---|---|---|
| Model | 1073.54 | 9 | 119.28 | 32.75 | <0.0001 |
| X 1-current density | 101.25 | 1 | 101.25 | 27.80 | 0.0012 |
| X 2-electrolyte | 365.72 | 1 | 365.72 | 15.75 | <0.0001 |
| X 3-plate spacing | 0.0741 | 1 | 0.0741 | 0.0203 | 0.8906 |
| X 1 X 2 | 0.0324 | 1 | 0.0324 | 0.0089 | 0.9275 |
| X 1 X 3 | 40.32 | 1 | 40.32 | 11.07 | 0.0126 |
| X 2 X 3 | 3.08 | 1 | 3.08 | 0.8456 | 0.3884 |
| X 1 2 | 160.43 | 1 | 160.43 | 44.05 | 0.0003 |
| X 2 2 | 108.67 | 1 | 108.67 | 29.84 | 0.0009 |
| X 3 2 | 236.54 | 1 | 236.54 | 64.94 | <0.0001 |
| Residual | 25.50 | 7 | 3.64 | ||
| Lack of fit | 15.32 | 3 | 5.11 | 2.01 | 0.2554 |
| Pure error | 10.18 | 4 | 2.54 | ||
| Cor total | 1099.03 | 16 | |||
| R 2 = 0.9768 | R aj 2 = 0.9470 | C.V.% = 2.26 | |||