Term Yield
Regression coefficients t-value p-value
Constant 49.5143 108.708 0.000
Ccp(mg/L) -3.6783 -14.933 0.000
pH -11.9833 -48.651 0.000
t (min) 2.7100 11.002 0.000
D (g) 2.0975 8.516 0.000
Ccp2(mg/L)2 0.6943 3.077 0.007
pH2 -5.6932 -25.229 0.000
t2(min)2 -1.2307 -5.454 0.000
D2(g)2 0.3181 1.410 0.178
pH × Ccp(mg/L) 1.0888 3.609 0.002
Ccp(mg/L) × t(min) -1.2462 -4.131 0.001
Ccp(mg/L) × D (g) -1.7562 -5.822 0.000
pH × t (min) 0.3338 1.106 0.285
pH × D (g) -1.6163 -5.358 0.000
t (min) × D (g) -0.8013 -2.656 0.017
Table 5: Observed Regression Coefficients, t-Test, and p-Values for 2-CP removal by Fe powder.