Table 2.

ANVOA analysis for RSM model.

Source of variance	SQ	df	MS	F value	p value
Model	0.77	14	0.055	8.72	< 0.0001**
X1	8.533E-03	1	8.533E-03	1.36	0.2621
X2	0.20	1	0.20	32.27	< 0.0001**
X3	0.072	1	0.072	11.74	0.0041**
X4	0.029	1	0.029	4.62	0.0484*
X12	0.15	1	0.15	23.47	0.0002**
X22	0.0049	1	0.0049	7.73	0.0140*
X32	0.066	1	0.066	10.46	0.0056**
X42	0.13	1	0.13	20.75	0.0004**
X1X2	3.025E-03	1	3.025E-03	0.48	0.4984
X1X3	9.000E-04	1	9.000E-04	0.14	0.7104
X1X4	0.070	1	0.070	11.17	0.0045**
X2X3	0.084	1	0.084	13.38	0.0023**
X2X4	9.025E-03	1	9.025E-03	1.44	0.2494
X3X4	4.225E-03	1	4.225E-03	0.67	0.4251
Residual	0.094	15	6.285E-0.003
Lack of fit	0.017	10	1.654E-0.003	0.11	0.9985
Pure error	0.078	5	0.016
Sum	0.86	29
	R2 = 0.8906		R2Adj = 0.7885	C.V. = 0.7595