Table 3.
ANOVA results for the response surface quadratic model for P removal efficiency
| Source | Sum of squares | Degree of freedom | Mean square | F value | p |
|---|---|---|---|---|---|
| Model | 7661.16 | 9 | 851.24 | 42.52 | 0.000s |
| X1 | 5125.78 | 1 | 5125.78 | 256.01 | 0.000s |
| X2 | 0.63 | 1 | 0.63 | 0.03 | 0.864n |
| X3 | 46.32 | 1 | 46.32 | 2.31 | 0.172n |
| X12 | 1592.85 | 1 | 1592.85 | 79.56 | 0.000s |
| X22 | 617.74 | 1 | 617.74 | 30.85 | 0.001s |
| X32 | 75.61 | 1 | 75.61 | 3.78 | 0.093n |
| X1X2 | 236.39 | 1 | 236.39 | 11.81 | 0.011s |
| X1X3 | 5.64 | 1 | 5.64 | 0.28 | 0.612n |
| X2X3 | 72.25 | 1 | 72.25 | 3.61 | 0.099n |
| Residual | 140.15 | 7 | 20.02 | – | – |
| Lack of fit | 112.45 | 3 | 37.48 | 5.41 | 0.068 |
| Pure error | 27.70 | 4 | 6.93 | – | – |
| Cor total | 7801.32 | 16 | – | – | – |
sSignificant at p < 0.05
nNot significant at p > 0.05