Research Article

Optimization Studies on Recovery of Metals from Printed Circuit Board Waste

Table 4

Coefficients in terms of coded factors for lead.

FactorCoefficient estimateDOFStandard error95% CI low95% CI highVIF

Intercept66.3613.9856.9675.76
A-CD9.0213.141.5916.451.0000
B-solvent7.3713.14−0.057314.801.0000
C-time6.4213.14−1.0113.851.0000
AB1.2414.44−9.2711.741.0000
AC0.170014.44−10.3410.681.0000
BC−7.1514.44−17.663.361.0000
A2−18.6214.33−28.86−8.381.01
B2−1.6714.33−11.918.571.01
C2−1.8214.33−12.068.431.01