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Student Support Forum: 'NonlinearModelFit vs GeneralizedLinearModelFit' topicStudent Support Forum > General > Archives > "NonlinearModelFit vs GeneralizedLinearModelFit"

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Jason Abernathy
01/28/10 5:07pm

Hello,

I am trying to fit a function to some data which represents the number of observations at a given life.

The function I would like to fit is b*Exp[-a*x]. However, when I use the two different fit methods (as shown in the attached .nb file) there are two different results.

The reason I ask is that I would like to include another term in the fit function so it is of the form b*Exp[-a*x] + c.

The fit result from the GeneralizedLinearModelFit seems to fit much better than the one from NonlinearModelFit.

My question is: how can I get Mathematica to give the same result for both functions so I can add a constant term to the NonlinearModelFit function?

Attachment: lifetime.nb, URL: ,
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