Table 5.
Analysis of variance showing effects of treatment variables as linear, quadratic terms and interaction effects on response variables of crude ash.

Source	Degree of freedom	Fine fraction		Coarse fraction
		F value	Pr>F	F value	Pr>F
Model	9	8.04	<0.001	7.30	<0.001
Liner	3	18.54	<0.001	18.01	<0.001
Quadratic	3	4.06	0.024	3.58	0.036
Cross	3	1.51	0.247	0.30	0.826
R2		0.810		0.800
X11)	4	16.77	0.001	16.53	0.001
X2	4	27.30	<0.001	32.26	<0.001
X3	4	11.54	0.003	5.24	0.035

Mill speed (rpm), Separator reverse wheel speed (rpm), Air classifier reverse wheel speed (rpm).