Table 4. Analysis of variance for the fitted quadratic polynomial model

Source	Sum of squares	Degree of freedom	Mean square	F-value	Prob > F
Model	145.99	9	16.22	146.28	< 0.0001
Residual	0.78	7	0.11
Lack of fit	0.53	3	0.18	2.83	< 0.0001
Pure error	0.25	4	0.062		0.1703
A	3.12	1	3.12	28.18	0.0011
B	2.21	1	2.21	19.88	0.0029
C	1.36	1	1.36	12.28	0.0099
AB	0.016	1	0.016	0.14	0.7185
AC	0.77	1	0.77	6.9	0.034
BC	0.8	1	0.8	7.22	0.0312
A2	42.6	1	42.6	384.16	< 0.0001
B2	38.17	1	38.17	344.19	< 0.0001
C2	42.46	1	42.46	382.95	< 0.0001
Cor total	146.76	16
	R2 = 0.9947	R2adj = 0.9879	CV = 0.62