Table 5. Analysis of variance for evaluation of the reduced third-order model.

Regression	Degrees of freedom	Type I sum of squares	r2	F-value	p-value
Covariates	5	0.42846	0.3054	14.37	<0.0001
Linear	4	0.56331	0.4016	23.61	<0.0001
Quadratic	4	0.20883	0.1489	8.75	0.0004
Cubic	4	0.09484	0.0676	3.98	0.0175
Total model	17	1.29544	0.9235	12.78	<0.0001
Residual	Degrees of freedom	Sum of squares	Mean square	F-value	p-value
Lack of fit	12	0.09168	0.00764	2.93	0.0985
Pure error	6	0.01567	0.00261
Total error	18	0.10734	0.00596