Table 2.
Statistical analysis of the Box-Behnken design
| Source | Sum of squares | Degree of freedom | Mean square | F-value | p-value (prob >F) |
|---|---|---|---|---|---|
| Model | 14,220.13 | 14 | 1015.72 | 9.26 | < 0.0001 |
| A-Starch | 781.77 | 1 | 781.77 | 7.13 | 0.0110 |
| B-KNO3 | 842.58 | 1 | 842.58 | 7.69 | 0.0085 |
| C-NaCl | 542.72 | 1 | 542.72 | 4.95 | 0.0319 |
| D-K2HPO4 | 276.29 | 1 | 276.29 | 2.52 | 0.1205 |
| E-Tryptophan | 108.14 | 1 | 108.14 | 0.99 | 0.3268 |
| F-Incubation time | 1320.17 | 1 | 1320.17 | 12.04 | 0.0013 |
| AC | 435.48 | 1 | 435.48 | 3.97 | 0.0533 |
| AE | 349.03 | 1 | 349.03 | 3.18 | 0.0822 |
| DF | 936.62 | 1 | 936.62 | 8.54 | 0.0057 |
| A2 | 1836.64 | 1 | 1836.64 | 16.75 | 0.0002 |
| B2 | 2273.38 | 1 | 2273.38 | 20.74 | < 0.0001 |
| C2 | 1569.56 | 1 | 1569.56 | 14.32 | 0.0005 |
| E2 | 3062.90 | 1 | 3062.90 | 27.94 | < 0.0001 |
| F2 | 789.01 | 1 | 789.01 | 7.20 | 0.0107 |
| Residual | 4275.65 | 39 | 109.63 | ||
| Lack of Fit | 3898.03 | 34 | 114.65 | 1.52 | 0.3430 |
| Pure Error | 377.63 | 5 | 75.53 |
R2 = 0.7688; Adj R2 = 0.6858; Pred R-squared = 0.5471