[R] surf.ls

[m p]

yes, that's true. I forgot about two linear terms.
Does anybody know what order the coefficients come
or where to find the answer?
M


--- Peter Dalgaard <p.dalgaard at biostat.ku.dk> wrote:

> m p <mzp3769 at yahoo.com> writes:
> 
> > Hello,
> > I am looking into description of surf.ls(spatial)
> > and see under value $beta - the coefficients.
> > When I use polynomial of degree 2 to fit surface
> > I expect to get 4 coefficients:
> > 
> > z = a_1 x^2 + a_2 xy + a_3 y^2 + a_4
> > 
> > What do beta really stand for and why do I get
> > $beta vector of length 6?
> 
> Why do you expect a constant term but no linear
> terms? I'm too lazy to
> verify, but it sounds like that would be your
> missing 2 coefficients.
> 
> -- 
>    O__  ---- Peter Dalgaard             Blegdamsvej
> 3  
>   c/ /'_ --- Dept. of Biostatistics     2200 Cph. N 
>  
>  (*) \(*) -- University of Copenhagen   Denmark     
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> ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)            
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>