Table 6 Box-Behnken statistics showing the coefficient values, t-values, and P-values for each variable of the design
Variable | Coefficients | t-statistics | P-value | Confidence level (%) |
|---|---|---|---|---|
Intercept | 546.9047619 | |||
x1 | 95.11904762 | 6.304373 | 0.003236 | 99.67638 |
x2 | 4.226190476 | 0.280107 | 0.793285 | 20.67154 |
x3 | 59.46428571 | 3.941219 | 0.016942 | 98.30576 |
x1 × 2 | 43.57142857 | 2.042026 | 0.110688 | 88.93115 |
x1 × 3 | 70.95238095 | 3.325266 | 0.029234 | 97.07655 |
x2 × 3 | -70.35714286 | -3.29737 | 0.030007 | 96.99927 |
x1 × 1 | -18.86904762 | -0.79096 | 0.473224 | 52.67762 |
x2 × 2 | 8.392857143 | 0.351815 | 0.742729 | 25.72712 |
x3 × 3 | 10.29761905 | 0.431659 | 0.688237 | 31.17627 |