Table 4. Results of variance analysis of oil recovery.
| Impact of effect |
SS | DF | MS | F | p |
|---|---|---|---|---|---|
| x1 (L+Q) | 405.622 | 2 | 202.811 | 14.015 | 0.00003 |
| x2 (L+Q) | 4741.486 | 2 | 2370.743 | 163.829 | 0.00000 |
| x3 (L+Q) | 744.888 | 2 | 372.444 | 25.738 | 0.00000 |
| x1·x2 | 126.555 | 1 | 126.555 | 8.745 | 0.00553 |
| x1·x3 | 28.923 | 1 | 28.923 | 1.999 | 0.16627 |
| x2·x3 | 115.779 | 1 | 115.779 | 8.001 | 0.00769 |
| Error | 506.479 | 35 | 14.471 | ||
| Total SS | 6446.314 | 44 |
x1=temperature, x2=pH, x3=time, L=linear effect, Q=quadratic effect, SS=sum of squares, DF=degree of freedom, MS=mean square value