Table 2.
Significance of linear, cross-product and quadratic terms on Y, TP, DPPH, FRAP and ABTS.
| Coefficients | Y | TP | DPPH | FRAP | ABTS |
|---|---|---|---|---|---|
| p-Value | |||||
| Linear | |||||
| X1-Ethanol concentration | <0.0001 * | 0.0001 * | <0.0001 * | 0.3235 | 0.0616 |
| X2-Extraction time | 0.0448 ** | 0.1554 | 0.0014 * | 0.6279 | 0.2024 |
| X3-Liquid–solid ratio | 0.0004 * | <0.0001 * | 0.6736 | 0.0339 | <0.0001 * |
| X4-Irradiation power | 0.2989 | 0.8638 | 0.5279 | 0.0545 | 0.5151 |
| Cross-product | |||||
| X1X2 | - | 0.1157 | 0.6323 | - | - |
| X1X3 | - | 0.0321 ** | 0.0161 ** | - | - |
| X1X4 | - | - | 0.5840 | - | 0.3010 |
| X2X3 | 0.0191 ** | - | 0.6873 | - | - |
| X2X4 | 0.2665 | 0.8809 | - | 0.2744 | - |
| X3X4 | - | 0.6695 | 0.2751 | - | - |
| Quadratic | |||||
| X12 | 0.0377 ** | 0.0090 * | 0.1226 | - | 0.0216 ** |
| X22 | 0.0729 | 0.7068 | 0.6754 | - | - |
| X32 | 0.2946 | 0.4842 | 0.0311 ** | - | - |
| X42 | 0.1989 | 0.8243 | - | 0.0098 * | 0.2836 |
* p < 0.01—significant, ** 0.01 < p < 0.05—moderately significant.