Table 3. Variance analysis for fitting quadratic model of extraction yield of PSC and PPN.

Source	Sum of square	Degree of freedom	Mean square	F-value	P-value
Extraction of PSC
Model	11.29	9	1.25	52.45	0.0002**
X1	0.11	1	0.11	4.42	0.0894
X2	0.065	1	0.065	2.71	0.1607
X3	0.94	1	0.94	39.24	0.0015*
X1X2	0.027	1	0.027	1.14	0.3348
X1X3	0.28	1	0.28	11.53	0.0194*
X2X3	1.27	1	1.27	52.93	0.0008**
X12	0.38	1	0.38	16.02	0.0103*
X22	3.63	1	3.63	151.97	<0.0001**
X32	5.51	1	5.51	230.6	<0.0001**
Residual	0.12	5	0.024
Lack of fit	0.1	3	0.034	4.23	0.197
Pure error	0.016	2	0.008133
Correlation Total	11.41	14
R2	0.9895	Adj R2	0.9707
C.V.%	0.99	Pred R2	0.8519
PRESS	1.69	Adeq Precision	23.991
Extraction of PPN
Model	2.09	9	0.23	16.76	0.0032*
X′1	0.6	1	0.6	43.73	0.0012*
X′2	0.66	1	0.66	47.8	0.001**
X′3	0.061	1	0.061	4.43	0.0893
X′1X′2	0.0025	1	0.0025	0.18	0.6884
X′1X′3	0.12	1	0.12	8.86	0.0309*
X′2X′3	0.04	1	0.04	2.89	0.1498
X′12	0.05	1	0.05	3.63	0.115
X′22	0.00641	1	0.00641	0.46	0.5263
X′32	0.57	1	0.57	40.95	0.0014*
Residual	0.069	5	0.014
Lack of fit	0.043	3	0.014	1.06	0.5183
Pure error	0.027	2	0.013
Correlation Total	2.16	14
R2	0.9679	Adj R2	0.9102
C.V.%	1.43	Pred R2	0.6568
PRESS	0.74	Adeq Precision	14.839

Notes.

^*Means significant at P < 0.05.

^**Means significant at P < 0.001.