Cu-Glucose Ratio Polynomial Fit

Fitting the Cu-Glucose Ratio Table

Using the Trendline function in Microsoft Excel 5.0, a third order polynomial was found to give a good fit to these empirical data.

Cu in mg

Cu-Glucose Ratio
3rd Poly
error




400
1.863
1.863
0.000
350
1.892
1.892
0.000
300
1.921
1.921
0.000
250
1.950
1.949
-0.001
200
1.978
1.978
0.000
150
2.008
2.008
0.000
100
2.041
2.040
-0.001
70
2.059
2.060
0.001
50
2.075
2.074
-0.001

The equation used in the third entry of the third column (C5 on the spreadsheet) was:

cell C5 = -0.0000000009096*A5^3 + 0.00000077181*A5^2 - 0.00078573*A5 + 2.1118

For use in a calculator, the more conventional form is

Y = -9.0960x10-10 X3 + 7.7181x10-7 X2 - 7.8573x10-4 X + 2.1118

Where Y= mgCu/mgGlucose and X = mg Cu found in your sample.

For questions or comments contact Dr. David L. Zellmer at david_zellmer@csufresno.edu.

Last updated 9 December 1996