Table 2.

Results of statistical (CCD) analysis for medium optimization

Model term	Coefficient estimate	Computed t value	p value	Confidence level (%)
			prob > F
(a) Model coefficient estimated by regressions
Intercept	0.443596	56.21	0*	100
CMC (X1)	0.087215	16.657	0*	100
Yeast extract (X2)	−0.028983	−5.535	0*	100
Peptone (X3)	−0.008664	−1.655	0.129	87.1
CMC × CMC	−0.045706	−8.967	0*	100
Yeast extract × yeast extract	0.008741	1.715	0.117	88.3
Peptone × peptone	−0.011942	−2.343	0.041*	95.9
CMC × yeast extract (X1 × X2)	0.0175	2.558	0.028*	97.2
CMC × peptone (X1 × X3)	0.02175	3.179	0.01*	99
Yeast extract × peptone (X2 × X3)	0.02975	4.349	0.001*	99.9

Source	DF	SS	MS	F value	p value
					prob > F
(b) ANOVA for quadratic model
Regression	9	0.163	0.0182	48.51	0
Linear	3	0.116	0.0388	103.61	0
Square	3	0.0338	0.0113	30.05	0
Interaction	3	0.0133	0.00444	11.85	0.001
Residual (error)	10	0.00374	0.000374
Lack of fit	5	0.00281	0.000561	2.99	0.127
Pure error	5	0.000938	0.000188
Total	19	0.167

DF degrees of freedom, SS sum of squares, MS mean square

* Significant p values, p ≤ 0.05; R² = 0.9776; predicted R² = 0.8642; adjusted R² = 0.9575