Table 3. Results of ANOVA Analysis for Quadratic Model Regression of the TPC in the Aqueous Extract of Olive Tree Leaves^a.

interaction type	source	TPC [μg GAE/mL]
		coefficient factor	SS	df	MS	F-value	p-value
	model	143.300	5750,334	9	638,926	119.874	<0.0001*
linear	x1	12.901	1331.538	1	1331.538	2493.984	<0.0001*
	x2	18.705	2799.016	1	2799.016	5242.585	<0.0001*
	x3	8.721	608.482	1	608.482	1139.692	<0.0001*
quadratic	x21	–4.195	74.097	1	74.097	138.784	0.0003*
	x22	–12.088	615.190	1	615.190	1152.257	<0.0001*
	x23	–7.340	226.845	1	226.845	424.882	<0.0001*
interaction	x1x2	–0.453	0.819	1	0.819	1.534	0.283
	x1x3	–1.250	6.250	1	6.250	11.706	0.027*
	x2x3	–0.808	2.608	1	2.608	4.885	0.092
residual			37.31	7	5.330
pure error			2.136	4	0.534
LoF			35.171	3	11.724	21.959	0.006*
core total			5787.644	16

^aNote: SD = 19.02; mean = 132.18; R² = 0.9936; R_adj² = 0.9853; R_pred² = 0.9948; coefficient of variation (CV) % = 14.3; adequate precision = 36.5057; PRESS = 30.2435; SS—sum of squares; MS—mean square; PRESS—predicted residual error sum of squares; df–degree of freedom; * significant for p < 0.05.