Elaine,

I suggest that you consult with a statistician to see if it even makes
sense to compare the two models you describe.  The first model makes sense
to me, the second one does not.  Isn't y2 in the second equation equal to
the estimated y1 from the first equation?  You need to talk with someone
about what you have, where it came from, and what questions you are trying
to answer.

Jean


On Fri, May 3, 2013 at 6:08 PM, Elaine Kuo <elaine.kuo.tw@gmail.com> wrote:

> Hello ,
>
> I want to compare two quadratic regression models with non-parametric
> bootstrap.
> However, I do not know which R package can serve the purpose,
> such as boot, rms, or bootstrap, DeltaR.
> Please kindly advise and thank you.
>
> Elaine
>
> The two quadratic regression models are
>
> y1=a1x^2+b1x+c1
>
> y1= observed migration distance of butterflies()
>
> y2=a2x^2+b2x+c2
>
> y2= predicted migration distance of butterflies (based on body mass)
>
> x= body mass of butterflies
>
>
> null hypothesis: a1=a2 and b1=b2 and c1=c2
>
> bootstrap to test if the coeffients (a, b, c) of the y1 and the y2 model
> differ
>
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>
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