| Independent variable |
Coefficient Symbol |
Soluble proteins (1) (Y1) |
NH2 –free amino groups (2) (Y2) |
| |
Estimate |
t-value |
P-value |
%confidence |
Estimate |
t-value |
P-value |
%confidence |
| B0 |
0.278816 |
19.28318 |
3.07E-09* |
99.99 |
40.40009 |
11.442 |
4.56E-07* |
99.99 |
| Feather(X1) |
B1 |
0.075021 |
6.879394 |
4.3E-05* |
99.99 |
15.22281 |
5.7165 |
0.000194* |
99.99 |
| Inoculum size(X61) |
B6 |
0.018603 |
1.705866 |
0.118844 |
|
5.77216 |
2.1675 |
0.055394 |
95.00 |
| Yeast extract(X3) |
B3 |
0.010944 |
1.003568 |
0.339252 |
|
1.178679 |
0.4426 |
0.667458 |
|
| X12 |
B11 |
-0.02982 |
-2.35315 |
0.040423* |
96.00 |
-6.46324 |
-2.088 |
0.063244 |
|
| X62 |
B66 |
-0.01298 |
-1.02437 |
0.329804 |
|
2.975538 |
0.9617 |
0.358881 |
|
| X32 |
B33 |
-0.02583 |
-2.01049 |
0.072116 |
|
6.990076 |
2.2284 |
0.049982 |
95.10 |
| X1.X6 |
B16 |
0.020707 |
1.540874 |
0.154372 |
|
1.532481 |
0.4670 |
0.650503 |
|
| X1.X3 |
B13 |
0.006293 |
0.468305 |
0.649607 |
|
-8.51998 |
-2.596 |
0.026656 |
97.40 |
| X3.X6 |
B36 |
0.040207 |
2.991949 |
0.013529* |
98.65 |
-5.20752 |
-1.587 |
0.14361 |
|
|
| • Highlighted significant model terms are taken at P<0.05 for the soluble protein model.
• Highlighted significant model terms are taken at P ≤ 0.06 for the NH2-free amino groups’ model.
(1): R2=0.87 and adjusted R2=0.76
(2): R2=0.87 and adjusted R2=0.75 |
| Table 6: Regression summary for full polynomial equation for end products of feather biodegradation upon using CCD. |
