Table 4. ANOVA of PBD for the Aluminum Adsorption Process^a.

source	sum of squares	degree of freedom	mean square	F-value	p-value
model	7588.38	7	1084.05	31.1000	0.0025
pH	3219.65	1	3219.65	92.3600	0.0007
speed	161.04	1	161.04	4.6200	0.0980
amount	2776.74	1	2776.74	79.6600	0.0009
temperature	166.36	1	166.36	4.7700	0.0943
contact time	1208.41	1	1208.41	34.6700	0.0042
type	52.50	1	52.50	1.5100	0.2870
GA	3.67	1	3.67	0.1054	0.7617

^aR² = 0.9820; adjusted R² = 0.9504; and predicted R² = 0.8376.