Table 2.

Estimated regression coefficients of the adjusted second-order polynomial equation and analysis of variance (ANOVA) of the model.

Regression Coefficients	Response
	TPC		ABTS		DPPH
	Effect	p Value	Effect	p Value	Effect	p Value
β0	20.9165 *	0.0000	25.5081 *	0.0000	16.4511 *	0.0001
Lineal
β1	−7.39159 *	0.0000	−6.9354 *	0.000	−7.1540 *	0.0036
β2	7.14405 *	0.0001	4.1242 *	0.0189	3.9375 *	0.0343
β3	0.1177	0.8784	−2.5229	0.6391	1.2579	0.7225
β4	5.0592 *	0.0002	−6.3625 *	0.0227	4.2319 *	0.0215
Crossed
β12	4.0196 *	0.0211	4.2385	0.1091	−4.5509 *	0.0274
β13	2.5322	0.0637	0.5152	0.7383	2.8321	0.0665
β14	2.1488	0.0855	1.9652	0.2811	2.7874	0.0684
β23	5.8083 *	0.0023	6.0598 *	0.0182	−2.2457	0.4190
β24	−0.5977	0.4677	−0.3305	0.8286	−1.3348	0.2248
β34	4.0099 *	0.0214	−10.1977 *	0.0005	0.6917	0.4634
Quadratic
β11	1.9745 *	0.0001	12.6447 *	0.0000	8.0299 *	0.0020
β22	−1.0824	0.1228	7.1362 *	0.0000	2.1692 *	0.03400
β33	−1.6717	0.0569	0.7439	0.4660	1.1751	0.1326
β44	−2.2687 *	0.0336	1.9455	0.1091	0.4520	0.3771
R2	0.9564		0.9286		0.8694
p Model	0.0011		0.0043		0.0001
p Lack of fit	0.1522		0.2624		0.1117

* Significant at α ≤ 0.05; 1 Ethanol/water ratio (v/v), 2 time, 3 amplitude, 4 pulse.