Re: [R] Linear Model with curve fitting parameter?

From: Steven McKinney <smckinney_at_bccrc.ca>
Date: Thu, 31 Mar 2011 18:34:07 -0700

> -----Original Message-----
> From: r-help-bounces_at_r-project.org [mailto:r-help-bounces_at_r-project.org] On Behalf Of stephen sefick
> Sent: March-31-11 3:38 PM
> To: R help
> Subject: [R] Linear Model with curve fitting parameter?
>
> I have a model Q=K*A*(R^r)*(S^s)
>
> A, R, and S are data I have and K is a curve fitting parameter. I
> have linearized as
>
> log(Q)=log(K)+log(A)+r*log(R)+s*log(S)
>
> I have taken the log of the data that I have and this is the model
> formula without the K part
>
> lm(Q~offset(A)+R+S, data=x)
>
> What is the formula that I should use?

Let Z = Q - A for your logged data.

Fitting lm(Z ~ R + S, data = x) should yield intercept parameter estimate = estimate for log(K) R coefficient parameter estimate = estimate for r S coefficient parameter estimate = estimate for s

Steven McKinney

Statistician
Molecular Oncology and Breast Cancer Program British Columbia Cancer Research Centre

>
> Thanks for all of your help. I can provide a subset of data if necessary.
>
>
>
> --
> Stephen Sefick
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Fri 01 Apr 2011 - 01:37:17 GMT

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