Subcritical Water Extraction of Chlorella pyrenoidosa: Optimization through Response Surface Methodology

Table 4

Selection of a suitable model for the SCW system (fit summary).

Source	Sum of squares	d.f.	Mean square	F	P > F	Remark
Sequential model sum of squares
Mean	0.051	1	0.051
Linear	0.018	3	6.105E-003	26.62	< 0.0001	Suggested
2FI	7.103E-004	3	2.368E-004	1.04	0.4075
Quadratic	1.463E-003	3	4.877E-004	3.26	0.0680	Suggested
Cubic	1.221E-003	5	2.443E-004	4.43	0.0639	Aliased
Residual	2.754E-004	5	5.509E-005
Total	0.073	20	3.642E-003
Lack-of-fit tests
Linear	3.395E-003	11	3.086E-004	5.60	0.0350	Suggested
2FI	2.684E-003	8	3.356E-004	6.09	0.0311
Quadratic	1.221E-003	5	2.443E-004	4.43	0.0639	Suggested
Cubic	0.000	0				Aliased
Pure Error	2.754E-004	5	5.509E-005
Model Summary statistics
Source	S.D.	R^2	Adj. R^2	Pre. R^2	PRESS	Remark
Linear	0.015	0.8331	0.8018	0.7157	6.251E-003	Suggested
2FI	0.015	0.8654	0.8032	0.5914	8.984E-003
Quadratic	0.012	0.9319	0.8707	0.5038	0.011	Suggested
Cubic	7.422E-003	0.9875	0.9524			Aliased