Table 7.

Regression analysis (ANOVA) of quadratic polynomial model and significance test.

Source	Sum of squares	df	Mean Square	F value	P value Prob. > F	Significance
Model	6959.86	9	773.32	45.19	<0.0001	Significant
Residual	119.79	7	17.11
Lack of fit	89.92	3	29.97	4.01	0.1064	Not significant
Pure error	29.87	4	7.47
Cor. total	7079.65	16

R ² = 0.9831, Adj R ² = 0.9613.