Table 3.

Student test of the different terms suggested for the essential oil extraction yield model

Factor	Coefficient	Standard Error	t	p
Constant	2.965	0.073	40.569	< 0.0001
x1	−2.278	0.090	− 25.450	< 0.0001
x2	0.858	0.090	9.590	< 0.001
x3	0.080	0.090	0.894	0.412
x12	−0.782	0.066	−11.875	< 0.0001
x22	−0.029	0.066	−0.446	0.674
x32	−0.047	0.066	−0.707	0.511
x1 × x2	−0.089	0.127	−0.703	0.513
x1 × x3	0.092	0.127	0.727	0.500
x2 × x3	−0.035	0.127	−0.277	0.793