Table 6.

Analysis of variance of the response surface quadratic model.

Source	DFa	Adj SSb	Adj MSc	F-value	P-value
Model	9	3.99061	0.44340	33.22	< 0.0001
X1	1	1.95502	1.95502	146.46	< 0.0001
X2	1	0.13981	0.13981	10.47	0.0089
X3	1	0.42885	0.42885	32.13	0.0002
X1X2	1	0.00002	0.00002	0.00	0.9714
X1X3	1	0.00088	0.00088	0.07	0.8024
X2X3	1	0.00065	0.00065	0.05	0.8301
X12	1	1.23057	1.23057	92.18	< 0.0001
X22	1	0.14479	0.14479	10.85	0.0081
X32	1	0.28321	0.28321	21.22	< 0.0010
Residual	10	0.13349	0.01335
Lack of fit	5	0.09443	0.01889	2.42	0.1774
Pure error	5	0.03906	0.00781
Total	19	4.12410

R² = 0.9676; adjusted R² = 0.9385; R = 0.9837.

^aDegree of freedom.

^bSum of squares.

^cMean square.