Re: [R] Coefficient of Determination for nonlinear function

2011-03-06 Thread Mike Marchywka
> From: uwe.wolf...@uni-ulm.de > To: andy_l...@merck.com > Date: Sat, 5 Mar 2011 17:14:12 +0100 > CC: r-help@r-project.org; gunter.ber...@gene.com > Subject: Re: [R] Coefficient of Determination for nonlinear function > >

Re: [R] Coefficient of Determination for nonlinear function

2011-03-05 Thread Uwe Wolfram
un...@r-project.org] On Behalf Of Bert Gunter > > Sent: Friday, March 04, 2011 11:21 AM > > To: uwe.wolf...@uni-ulm.de; r-help@r-project.org > > Subject: Re: [R] Coefficient of Determination for nonlinear function > > > > The coefficient of determination, R^2, is a

Re: [R] Coefficient of Determination for nonlinear function

2011-03-04 Thread Dieter Menne
Uwe Wolfram wrote: > > > I did fit an equation of the form 1 = f(x1,x2,x3) using a minimization > scheme. Now I want to compute the coefficient of determination. Normally > I would compute it as > > r_square = 1- sserr/sstot with sserr = sum_i (y_i - f_i) and sstot = > sum_i (y_i - mean(y)) >

Re: [R] Coefficient of Determination for nonlinear function

2011-03-04 Thread Bert Gunter
tical measure. > > Andy > >> -Original Message- >> From: r-help-boun...@r-project.org >> [mailto:r-help-boun...@r-project.org] On Behalf Of Bert Gunter >> Sent: Friday, March 04, 2011 11:21 AM >> To: uwe.wolf...@uni-ulm.de; r-help@r-project.org >> Sub

Re: [R] Coefficient of Determination for nonlinear function

2011-03-04 Thread Liaw, Andy
rom: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Bert Gunter > Sent: Friday, March 04, 2011 11:21 AM > To: uwe.wolf...@uni-ulm.de; r-help@r-project.org > Subject: Re: [R] Coefficient of Determination for nonlinear function > > The coefficient

Re: [R] Coefficient of Determination for nonlinear function

2011-03-04 Thread Bert Gunter
The coefficient of determination, R^2, is a measure of how well your model fits versus a "NULL" model, which is that the data are constant. In nonlinear models, as opposed to linear models, such a null model rarely makes sense. Therefore the coefficient of determination is generally not meaningful

[R] Coefficient of Determination for nonlinear function

2011-03-04 Thread Uwe Wolfram
Dear Subscribers, I did fit an equation of the form 1 = f(x1,x2,x3) using a minimization scheme. Now I want to compute the coefficient of determination. Normally I would compute it as r_square = 1- sserr/sstot with sserr = sum_i (y_i - f_i) and sstot = sum_i (y_i - mean(y)) sserr is clear to me

[R] Coefficient of Determination for nonlinear function

2011-03-04 Thread Uwe Wolfram
Dear Subscribers, I did fit an equation of the form 1 = f(x1,x2,x3) using a minimization scheme. Now I want to compute the coefficient of determination. Normally I would compute it as r_square = 1- sserr/sstot with sserr = sum_i (y_i - f_i) and sstot = sum_i (y_i - mean(y)) sserr is clear to me