Response Surface Methodology for Biodiesel Production Using Calcium Methoxide Catalyst Assisted with Tetrahydrofuran as Cosolvent

Table 3

ANOVA for the response surface quadratic model.

Source of variation	Sum of squares	df	Mean square	F-value	value	Significant at 5% level
Model	2957.24	14	211.23	20.65	<0.0001	Yes
	81.96	1	81.96	8.01	0.0127	Yes
	1541.28	1	1541.28	150.69	<0.0001	Yes
	145.88	1	145.88	14.26	0.0018	Yes
	140.12	1	140.12	13.70	0.0021	Yes
	6.31	1	6.31	0.62	0.4443	No
	0.11	1	0.11	0.011	0.9174	No
	2.23	1	2.23	0.22	0.6474	No
	6.14	1	6.14	0.60	0.4506	No
	71.11	1	71.11	6.95	0.0187	Yes
	6.64	1	6.64	0.65	0.4329	No
	114.74	1	114.74	11.22	0.0044	Yes
	880.73	1	880.73	86.11	<0.0001	Yes
	70.46	1	70.46	6.89	0.0191	Yes
	1.03	1	1.03	0.10	0.7550	No
Residual	153.42	15	10.23	4.30	0.0604	No
Lack of fit	137.45	10	13.74
Pure error	15.97	5	3.19
Cor total	3110.66	29

= degree of freedom; is not significantly different at the 5% level.