Table 2.

Analysis of variance of regression coefficients and statistical indicators of second order model for extraction yield (Y₁) and total phenols content (Y₂)

	Y 1		Y 2
	Coefficient	p value	Coefficient	p value
X a1	− 0.360	0.0249*	0.378	0.0636
X a2	8.693	< 0.0001**	0.791	0.0032*
X 1 X 2	1.447	0.0058**	0.437	0.0757
$X_1^2$	− 0.3	0.5052	− 0.916	0.0105*
$X_2^2$	− 9.240	< 0.0001**	− 0.926	0.0100*
Lack of fit	(p = 0.873)		(p = 0.778)
R2	99.61%		92.41%
Adj-R2	99.27%		86.09%
Standard errorb	0.691		0.408

^a Temperature (X₁); pressure (X₂)

^b Standard error relative to Y₁ and Y₁ values

**highly significant (p < 0.01)

*significant (0.01 < p < 0.05)