TABLE 4.
a) Analysis of variance (ANOVA) of the results for the response of cellulose (%) content from alkali pretreatment of corn stover. (b) ANOVA of the results for the response of lignin (%) content from alkali pretreatment of corn stover.
| (a) | ||||||
|---|---|---|---|---|---|---|
| Source | SS | Df | Mean square | F-value | p-value | |
| Model | 1871.73 | 5 | 374.346 | 39.64 | 0.00 | Significant |
| Linear | 840.67 | 2 | 420.336 | 44.51 | 0.00 | |
| NaOH | 679.47 | 1 | 679.47 | 71.95 | 0.00 | |
| Time | 161.20 | 1 | 161.202 | 17.07 | 0.004 | |
| Square | 741.38 | 2 | 370.688 | 39.25 | 0.00 | |
| NaOH × NaOH | 632.55 | 1 | 632.549 | 66.98 | 0.00 | |
| Time × Time | 0.00 | 1 | 0.004 | 0.00 | 0.984 | |
| Two-way interaction | 289.68 | 1 | 289.68 | 30.67 | 0.001 | |
| NaOH × Time | 289.68 | 1 | 289.68 | 30.67 | 0.001 | |
| Error | 66.11 | 7 | 9.444 | |||
| Lack of fit | 13.12 | 3 | 4.374 | 0.33 | 0.805 | |
| Pure error | 52.98 | 4 | 13.246 | |||
| Model statistics | ||||||
| R2 | 96.59 | |||||
| Adj-R2 | 94.15 | |||||
| Pred-R2 | 89.86 | |||||
| (b) | ||||||
| Source | SS | Df | Mean square | F-value | p-value | |
| Model | 406.11 | 5 | 81.222 | 288.85 | 0.000 | Significant |
| Linear | 386.579 | 2 | 193.29 | 687.4 | 0.000 | |
| NaOH | 382.561 | 1 | 382.561 | 1,360.51 | 0.000 | |
| Time | 4.018 | 1 | 4.018 | 14.29 | 0.007 | |
| Square | 18.628 | 2 | 9.314 | 33.12 | 0.000 | |
| NaOH × NaOH | 14.525 | 1 | 14.525 | 51.66 | 0.000 | |
| Time × Time | 0.177 | 1 | 0.177 | 0.63 | 0.453 | |
| Two-way interaction | 0.902 | 1 | 0.902 | 3.21 | 0.116 | |
| NaOH × Time | 0.902 | 1 | 0.902 | 3.21 | 0.116 | |
| Error | 1.968 | 7 | 0.281 | 0.000 | ||
| Lack of fit | 0.86 | 3 | 0.287 | 1.03 | 0.467 | |
| Pure error | 1.108 | 4 | 0.277 | 0.000 | ||
| Model statistics | ||||||
| R2 | 99.52 | |||||
| Adj-R2 | 99.17 | |||||
| Pred-R2 | 98 | |||||