Study of Montmorillonite Clay for the Removal of Copper (II) by Adsorption: Full Factorial Design Approach and Cascade Forward Neural Network

Table 4

Estimated effects and coefficients for % (coded units).

Term	Effect	Coefficient	SE	-test	value	Remark
Constant		80.1125	0.1971	406.48	0.000	Significant
	17.7000	8.8500	0.1971	44.90	0.000	Significant
	10.7250	5.3625	0.1971	27.21	0.000	Significant
	3.0000	1.5000	0.1971	7.61	0.001	Significant
	8.7750	4.3875	0.1971	22.26	0.000	Significant
	0.1500	0.0750	0.1971	0.38	0.719
	−0.3750	−0.1875	0.1971	−0.95	0.385
	−0.2500	−0.1250	0.1971	−0.63	0.554
	−0.5000	−0.2500	0.1971	−1.27	0.260
	1.0250	0.5125	0.1971	2.60	0.048	Significant

SE: standard errors, standard deviation = 0.78, PRESS = 31.82, = 99.85%, (predicted) = 98.46%, and (adjusted) = 99.55%.