[R] what characteristics of model curve do parameters denote

Dear list, I'm trying to fit a chapman-richards equation to my data, only I cannot interpret the parameters a, b and d. I know that the parameter b denotes the asymptote, but for the others I couldn't figure out. But I do need to know this in order to set my starting values. Here's the model: mod

Re: [R] R² for non-linear model + comparing linear + non-linear models

-Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Anna Gretschel Sent: Wednesday, March 16, 2011 2:09 PM To: Bert Gunter Cc: r-help@r-project.org Subject: Re: [R] R² for non-linear model + comparing linear + non-linear models Dear Bert, so what

Re: [R] R² for non-linear model + comparing linear + non-linear models

ay this because you have just been told that the "theory" tells you that you CANNOT calculate R^2 for a nonlinear model. On Wed, Mar 16, 2011 at 10:25 AM, Anna Gretschel wrote: Am 16.03.2011 18:15, schrieb David Winsemius: On Mar 16, 2011, at 12:53 PM, Anna Gretschel wrote: Dear Li

Re: [R] R² for non-linear model

* be "defined" come with their own sets of problems. A more precise definition of what you want (say you have a particular formula but do not know how to get the necessary information out of the model) may get a better answer. Best regards, Josh On Wed, Mar 16, 2011 at 9:53 AM, Anna

Re: [R] R² for non-linear model

Am 16.03.2011 18:15, schrieb David Winsemius: On Mar 16, 2011, at 12:53 PM, Anna Gretschel wrote: Dear List, how can I obtain the value of r suqared for a non-linear model? For linear models it can be found in the summary() of the model but for non-linear models I just don't know. P

[R] R² for non-linear model

Dear List, how can I obtain the value of r suqared for a non-linear model? For linear models it can be found in the summary() of the model but for non-linear models I just don't know. Please help! Anna __ R-help@r-project.org mailing list https://stat

[R] predicting values from model function

Dear List, I have fitted a spherical function to my variogram using "variofit(...)" from GeoR. Now I would like to predict some data with the function "predict(object,...)" from package stats. Does anyone know wether this works and if it does how to do it? Thanks a lot! Anna ___

[R] testing power of correlation

Dear List, does anyone know how I can test the strength of a correlation? Cheers, Anna __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and p