[R-br] ajuste com nls

[Cesar Rabak]

Em 11/7/2011 09:16, Gilson Sanchez escreveu:
> Pessoal mais uma vez procuro ajuda de vc's,
> consegui ajustar um modelo com nls, mas agora o que quero saber como eu
> faço para estimar o coeficiente (R2) e ver se a equação ajustou
> corretamente.
> obrigado
>

Gilson,

Veja esta 'thread' 
https://stat.ethz.ch/pipermail/r-help/2005-June/072898.html e em 
particular veja a citação:

"There is a good reason that an nls model fit in R does not provide
r-squared - r-squared doesn't make sense for a general nls model.

One way of thinking of r-squared is as a comparison of the residual
sum of squares for the fitted model to the residual sum of squares for
a trivial model that consists of a constant only. You cannot
guarantee that this is a comparison of nested models when dealing with
an nls model. If the models aren't nested this comparison is not
terribly meaningful.


   So the answer is that you probably don't want to do this in the first
place."

HTH,

> --
> MSc. Gilson Sánchez Chia
>
> Laboratório de Fisiologia Vegetal
>
> Embrapa Amazônia Ocidental
>
> Fone: (92) 3303-7841
>
> ---
> Antes de imprimir, pense na sua responsabilidade com o Meio Ambiente.
> Please consider the environment before printing this email.
> Renew, Reduce and Recycle. The Planet Knows.
>
>
>
> _______________________________________________
> R-br mailing list
> R-br em listas.c3sl.ufpr.br
> https://listas.inf.ufpr.br/cgi-bin/mailman/listinfo/r-br
> Leia o guia de postagem (http://www.leg.ufpr.br/r-br-guia) e forneça código mínimo reproduzível.


-- 
Cesar Rabak
GNU/Linux User 52247.
Get counted: http://counter.li.org/