Table 3.

Assessment of the significance of the model

Source	DF	Sum of squares	Mean square	F value	P value
Model	9	938.741	104.305	11.81	0.007
Linear	3	923.681	307.894	34.86	0.001
X (mg/L)	1	826.836	826.836	93.60	0.000
Y (mM)	1	81.920	81.920	9.27	0.029
Z (g/L)	1	14.925	14.925	1.69	0.250
Square	3	8.912	2.971	0.34	0.801
X (mg/L)*X (mg/L)	1	6.620	6.620	0.75	0.426
Y (mM)*Y (mM)	1	0.719	0.719	0.08	0.787
Z (g/L)*Z (g/L)	1	0.399	0.399	0.05	0.840
2-way interaction	3	6.147	2.049	0.23	0.871
X (mg/L)*Y (mM)	1	5.135	5.135	0.58	0.480
X (mg/L)*Z (g/L)	1	0.681	0.681	0.08	0.792
Y (mM)*Z (g/L)	1	0.332	0.332	0.04	0.854
Error	5	44.167	8.833
Total	14	982.909