[R] nls: how do you know if the model is significant?

[mkm1616]

Here goes bert again with etiquette lessons.

Why are you so crabby?

On Jun 5, 11:16 am, Bert Gunter <gunter.ber... at gene.com> wrote:
> I suggest you consult a local statistician. You could also post to a
> statistical help list like stats.stackexchange.com. Your query has
> nothing to do with R, but is rather about the meaningfulness (or lack
> thereof) of statistical significance in nonlinear modeling.
>
> -- Bert
>
>
>
>
>
> On Tue, Jun 5, 2012 at 6:49 AM, Nerak <nera... at hotmail.com> wrote:
> > Hi all,
> > I'm struggling with nls. How do you know if your model is significant? For a
> > lm, you get a p-value, but you don't get it for a nls. Is there a way to
> > calculate it?
>
> > For a lm I use this:
> >  a<-summary(lm(model ~obs))
> >  f.stat<-a$fstatistic
> >  p.value<-1-pf(f.stat["value"],f.stat["numdf"],f.stat["dendf"])
>
> > Is there something similar for a nls?
>
> > The kind of output that I get is:
>
> > Formula: y ~ exp.f(x, a, b)
>
> > Parameters:
> >   Estimate Std. Error t value Pr(>|t|)
> > a 1.381e+02  1.192e+01  11.583 3.19e-08 ***
> > b 1.790e-02  2.459e-03   7.279 6.19e-06 ***
> > ---
> > Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
>
> > Residual standard error: 13.21 on 13 degrees of freedom
>
> > Number of iterations to convergence: 6
> > Achieved convergence tolerance: 9.123e-06
>
> > I know that my parameters are significant but I need to say something about
> > the whole model.
>
> > Many thanks,
> > Nerak
>
> > --
> > View this message in context:http://r.789695.n4.nabble.com/nls-how-do-you-know-if-the-model-is-sig...
> > Sent from the R help mailing list archive at Nabble.com.
>
> > ______________________________________________
> > R-h... at r-project.org mailing list
> >https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> --
>
> Bert Gunter
> Genentech Nonclinical Biostatistics
>
> Internal Contact Info:
> Phone: 467-7374
> Website:http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pd...
>
> ______________________________________________
> R-h... at r-project.org mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.- Hide quoted text -
>
> - Show quoted text -