Table 2.

Variance analysis of experimental results of RSM

Source	Df	Ferulic acid				Vanilla acid
		Sum of squares	Mean square	F value	p value	Sum of squares	Mean square	F value	p value
Model	9	1363.5	151.5	516.6	< 0.0001	920.0	102.2	183.3	< 0.0001
X 1	1	844.6	844.6	2879.8	< 0.0001	378.8	378.8	679.4	< 0.0001
X 2	1	15.68	15.68	53.46	0.0002	0.038	0.038	0.068	0.8020
X 3	1	1.8	1.8	6.15	0.0422	7.18	7.18	12.88	0.0089
X 1 X 2	1	0.0025	0.0025	0.00852	0.9290	7.02	7.02	12.59	0.0094
X 1 X 3	1	0.022	0.022	0.077	0.7898	1.48	1.48	2.65	0.1477
X 2 X 3	1	0.12	0.12	0.42	0.5387	3.08	3.08	5.52	0.0511
X 21	1	484.5	484.5	1652.1	< 0.0001	434.8	434.8	779.7	< 0.0001
X 22	1	2.88	2.88	9.83	0.0165	46.03	46.03	82.56	< 0.0001
X 23	1	2.55	2.55	8.68	0.0215	12.15	12.15	21.8	0.0023
Residual	7	2.05	0.29			3.9	0.56
Lack of fit	3	0.67	0.22	0.64	0.6287	1.48	0.49	0.81	0.5508
Pure error	4	1.39	0.35			2.43	0.61
Cor total	16	1365.6				923.9
SD		0.54					0.75
R2		0.9985					0.9958
Adj R2		0.9966					0.9903
Pred R2		0.9906					0.9703
Adeq precision		52.22					37.726
C.V. %		0.61					0.96