Table 2.

ANOVA for the regression model.

Source	Sum of Squares	DF	Mean Square	F-Value	p-Value	Significant
Model	0.76	14	0.054	14.24	<0.0001	**
X 1	0.065	1	0.065	16.96	0.0010	**
X 2	0.028	1	0.028	7.37	0.0168	*
X 3	0.013	1	0.013	3.33	0.0893
X 4	0.044	1	0.044	11.67	0.0042	**
X 1 X 2	0.013	1	0.013	3.48	0.0833
X 1 X 3	2.500 × 10−5	1	2.500 × 10−5	6.57 × 10−3	0.9365
X 1 X 4	1.600 × 10−3	1	0.0016	0.42	0.5271
X 2 X 3	0.053	1	0.053	13.91	0.0022	**
X 2 X 4	2.025 × 10−3	1	2.025 × 10−3	0.53	0.4777
X 3 X 4	4.000 × 10−4	1	4.000 × 10−3	0.11	0.7505
X 1 2	0.11	1	0.11	28.93	<0.0001	**
X 2 2	0.23	1	0.23	60.11	<0.0001	**
X 3 2	0.37	1	0.37	97.40	<0.0001	**
X 4 2	0.067	1	0.067	17.57	0.0009	**
Residual	0.053	14	3.804 × 10−3
Lack of fit	0.048	10	4.818 × 10−3	3.79	0.1053
Pure error	5.080 × 10−3	4	1.270 × 10−3
Cor total	0.81	28
CV%			2.93%
R 2			0.9344
adj-R2			0.8688

Notes: ** p < 0.01 extremely significant; * p < 0.05 significant.