Table 2. Box–Behnken Factorial Design with the Independent Variables and Experimental and Predicted TPC Values in Aqueous Olive Tree L. Extract^a.

run	coded variable			actual variable			TPC [μg GAE/mL]
	x1 [g/mL]	x2 [°C]	x3 [min]	X1 [g/mL]	X2 [°C]	X3 [min]	actual	predicted	residual
1	–1	–1	0	0.008	50	70	97.13	94.96	2.17
2	1	–1	0	0.016	50	70	121.47	121.67	–0.20
3	–1	1	0	0.008	90	70	133.47	133.27	0.20
4	1	1	0	0.016	90	70	156.00	158.17	0.10
5	–1	0	–1	0.008	70	50	109.13	108.89	0.12
6	1	0	–1	0.016	70	50	139.80	137.20	–2,17
7	–1	0	1	0.008	70	90	126.23	128.84	–2.61
8	1	0	1	0.016	70	90	151.90	152.14	–0.24
9	0	–1	–1	0.012	50	50	93.23	95.64	–2,41
10	0	1	–1	0.012	90	50	134.23	134.66	–0.43
11	0	–1	1	0.012	50	90	115.13	114.70	0.43
12	0	1	1	0.012	90	90	152.90	150.49	2.41
13	0	0	0	0.012	70	70	143.90	143.30	0.30
14	0	0	0	0.012	70	70	144.13	143.30	0.83
15	0	0	0	0.012	70	70	143.33	143.30	0.03
16	0	0	0	0.012	70	70	142.67	143.30	–0.63
17	0	0	0	0.012	70	70	142.47	143.30	–0.83

^aNote: x₁ and X₁—biomass weight/extraction solvent ratio, x₂ and X₂—extraction temperature [°C], and x₃ and X₃—extraction time [min].