Table 3.

Analysis of variance (ANOVA) for the regression equation.

Source	Sum of squares	Degrees of freedom	Mean square	F value	p value
Model	281.13	9	31.24	1057.31	<0.0001
X1	14.50	1	14.50	490.77	<0.0001
X2	4.61	1	4.61	155.89	<0.0001
X3	11.23	1	11.23	380.25	<0.0001
X1X2	1.73	1	1.73	58.53	0.0001
X1X3	0.49	1	0.49	16.59	0.0047
X2X3	0.14	1	0.14	4.63	0.0683
X12	157.95	1	157.95	5346.26	<0.0001
X22	37.89	1	37.89	1282.46	<0.0001
X32	30.97	1	30.97	1048.41	<0.0001
Residual	0.21	7	0.030
Lack of fit	0.15	3	0.050	3.60	0.1239