Model term Coefficient F-value p-value
Constant -0.85776    
PH 1.52437 10.67 0.008
L -0.00453 0.06 0.818
Y 3.38646 3.88 0.077
T 0.37703 5.36 0.043
PH2 -0.15354 17.77 0.002
L2 -0.00006 0.42 0.533
Y2 -4.65104 26.09 0.000
T2 -0.00600 6.95 0.025
PH-L 0.00119 0.60 0.456
PH-T -0.00156 0.04 0.842
PH-Y 0.18125 1.40 0.262
L-T -0.00008 0.04 0.842
L-Y 0.00906 1.40 0.264
Y-T 0.00781 0.04 0.842
R2=92.05% and adjusted R2=80.91%
Table 2: Coefficient estimates and analysis of variance (ANOVA) for the response surface quadratic model.