Table 7.

The analysis of variance of optimization experimental design for loss of substrate mass by keratynolytic strains

ANOVA for response surface quadratic model
Source	Sum of squares	df	Mean square	F value	p
Model	15,786.23	9	1754.026	62.19	<0.0001*
X1	0.22	1	0.22	0.008	0.930
X2	5037.98	1	1364.19	48.37	<0.0001*
X3	1591.25	1	5037.98	178.64	<0.0001*
X21	1364.19	1	2139.41	75.86	<0.0001*
X22	2139.41	1	1591.25	56.42	<0.0001*
X23	3738.37	1	3738.37	132.55	<0.0001*
X1X2	136.44	1	136.44	4.83	<0.0001*
X1X3	69.91	1	69.90	2.47	0.124
X2X3	3.68	1	3.68	0.13	0.720
Residual	987.06	35	28.20
Lack of fit	189.19	3	63.06
Pure error	797.87	32	24.93
Cor total	16,773.29	44

* Significant at 5% level; R ² = 0.9411; $R_{\text{adj}}^2$ = 0.9260