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 Nonlinear fitting on a log scale

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Maxxpower3 Posted - 10/21/2011 : 12:46:47 PM
Origin Ver. and Service Release (Select Help-->About Origin): 8.0987
Operating System: Windows 7

Hello,

I am attempting to do some non-linear data fitting where my data is plotted on a log-log scale. I have defined my own equation, which is used to model light scattering from inhomogeneous materials.

The data at low X values has very large corresponding Y values and the data at large X values has small corresponding Y values.

The problem I have is that origin preferentially fits to the very high Y value portion (low X values) of the data and the rest of the data is very poorly fit.

I am looking for any help on how to make origin give equal weight to values which span many orders of magnitude.

Cheers
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Drbobshepherd Posted - 10/21/2011 : 6:03:42 PM
What's your criterion for a "good" fit? Do you want to minimize the variance for the y-values or the log(y) values?

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