Table 2.

Results of the statistical analysis of the central composite experimental design for valeric acid production.

	Coefficient estimate	t-Value	p-Value
Intercept	12.55	20.74	<0.0001
X1	0.42	0.87	0.4123
X2	−2.66	−5.57	0.0008
X1X2	0.40	0.59	0.5730
X12	−0.59	−1.11	0.3042
X22	−2.95	−5.76	0.0007
		F-Value	p -Value
Model		13.11	0.0019
Lack of fit		4.81	0.0815

R² = 90.35%, R² (adjusted) = 83.46%.