Table 5. Results of the ANOVA for the regression equation.

Source	DF	SS	MS	F-value	P-value Prob>F
Model	14	476.94	34.07	53.94	<0.0001
X1- Glucose	1	125.26	125.26	198.33	<0.0001
X2-CaCl2·2H2O	1	30.24	30.24	47.88	<0.0001
X3- Temperature	1	0.052	0.052	0.082	0.7783
X4-The inoculation amount	1	12.06	12.06	19.10	0.0006
X1 X2	1	22.00	22.00	34.83	< 0.0001
X1 X3	1	0.093	0.093	0.15	0.7069
X1 X4	1	0.036	0.036	0.057	0.8145
X2 X3	1	0.24	0.24	0.37	0.5515
X2 X4	1	0.58	0.58	0.91	0.3551
X3 X4	1	11.87	11.87	18.79	0.0007
X12	1	104.76	104.76	165.88	< 0.0001
X22	1	144.59	144.59	228.94	< 0.0001
X32	1	120.57	120.57	190.91	< 0.0001
X42	1	45.94	45.94	72.74	< 0.0001
Residual	14	8.84	0.63
Lack of Fit	10	4.37	0.44	0.39	0.8961
Pure Error	4	4.47	1.12
Cor Total	28	485.78
Coefficient of determination R2 = 0.9818		Adjusted coefficient of determination R2 = 0.9636		Mean = 48.28	Coefficient of variation (CV) = 1.65%

Note: P> 0.05, insignificant difference; P <0.05, significant difference; P <0.01, significant difference.