Model #

Independent variable(s)

Predictive Model

R² value

33.

As

$\widehat{Fe}$ = 9.80 As + 829.09

38.8%

34.

Cd

$\widehat{Fe}$ = 7.58 Cd + 1740.04

18.2%

35.

Co

$\widehat{Fe}$ = 9.53 Co + 1358.70

30.7%

36.

Cr

$\widehat{Fe}$ = 8.07 Cr + 1594.97

25.8%

37.

Pb

$\widehat{Fe}$ = 4.54 Pb + 1175.53

12.0%

38.

Sb

$\widehat{Fe}$ = 9.31 Sb − 469.23

51.0%

39.

Tl

$\widehat{Fe}$ = 9.50 Tl + 1446.20

30.0%

40.

As, Cd, Co, Cr, Pb, & Tl

$\widehat{Fe}$ = 11.31 As − 88.36 Cd + 38.35 Co +35.14 Cr − 1.95 Pb + 7.52 Tl − 457.25

86.9%