[R] How can I extract information from list which class is nls

[Gabor Grothendieck]

On Tue, Apr 26, 2011 at 2:21 PM, Schatzi <adele_thompson at cargill.com> wrote:
> How do I extract the standard error of the parameter estimates?
>
> Also, if I would like to add two parameters together (x+y), can I use this
> equation to calculate the new standard error?:
> x = parameter 1
> y = parameter 2
> xSE = SE parameter 1
> ySE = SE parameter 2
>
> NewSE=(x+y)*sqrt((xSE/x)^2+(ySE/y)^2)

Try taking the square roots of their variance:

> example(nls)
> sqrt(diag(vcov(fm1DNase1)))
      Asym       xmid       scal
0.07815395 0.08135321 0.03227080
>
> # it gives the same result as another solution
> # offered on this thread
> coef(summary(fm1DNase1))[, "Std. Error"]
      Asym       xmid       scal
0.07815395 0.08135321 0.03227080


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