Model #

Independent variable(s)

Predictive Model

R2 value

17.

As

C o ^ = 0.89 As − 37.80

95.2%

18.

Cd

C o ^ = 1.02 Cd + 29.34

96.9%

19.

Cr

C o ^ = 0.92 Cr + 20.44

98.2%

20.

Fe

C o ^ = 0.03 Fe + 10.79

30.7%

21.

Pb

C o ^ = 0.48 Pb − 19.78

38.8%

22.

Sb

C o ^ = 0.59 Sb − 83.60

59.4%

23.

Tl

C o ^ = 0.98 Tl − 10.72

93.4%

24.

As, Cd, Fe, Pb, & Sb

C o ^ = 0.10 As + 0.82 Cd + 0.01 Fe + 0.03 Pb + 0.03 Sb − 0.90

99.3%