Table 4. Analysis of variance for the final model

Regression	DF	Sum of squares	R-square	F-value	p-value
Linear	5	1.601320	0.3190	21.60	0.0000
Quadratic	5	0.234238	0.0467	3.16	0.0476
2-Way interactions	10	0.926281	0.1845	6.25	0.0020
3-Way interactions	10	1.443231	0.2875	9.73	0.0002
4-Way interactions	5	0.637441	0.1270	8.60	0.0012
Total model	35	4.842511	0.9646	9.33	0.0001

Residual	DF	Sum of squares	Mean square	F-value	p-value
Lack of fit	7	0.145237	0.020748	3.17	0.1110
Pure error	5	0.032683	0.006537
Total error	12	0.177921	0.014827

DF, degrees of freedom.