Re: st: Weighted Least Squares

 From Maarten buis To statalist@hsphsun2.harvard.edu Subject Re: st: Weighted Least Squares Date Tue, 15 Apr 2008 17:53:48 +0100 (BST)

```Sorry, but I still do not understand your question. It may help if you

what is the purpose of your analysis?

-- Maarten

--- Tam Phan <tamdphan@gmail.com> wrote:

> Maarten, X1 = % and X2= %, however, X1 +X2 does not necessary have to
> add up to 100% (as a matter of fact they dont).
>
> The % are calculated based on the zone, they are not calcualted
> across
> zone (say zone 1 and zone 2).
>
> Basically the explanatory variables are at a zone level, however, the
> regression is taking place at a higher level.  In order to "adjust"
> the zone explanatory varaibles, these are weighted to the higher
> level.
>
> Tam
>
> On 4/15/08, Maarten buis <maartenbuis@yahoo.co.uk> wrote:
> > - you have two (or more) variables: x1 = % in zone1, and x2 = % in
> >  zone 2, which must add up to 100%
> > - x1 and x2 are explanatory variables
> > - you want these variables to have only one effect instead two (or
> >  more) because you see them as one variable.
> >
> > Is that correct?
> >
> > -- Maarten
> >
> >
> > --- Tam Phan <tamdphan@gmail.com> wrote:
> >
> > > Hello Stata Users:
> > >
> > > I have a quick question on weighted Least squares:  Below is the
> > > following econometric equation:
> > >
> > > Q1+Q2 = alpha + [  (Q1/(Q1+Q2))*X1 + (Q2/(Q1+Q2))*X2 ]b + e
> > >
> > > Where X1 and X2 are the same explanatory variables, however with
> > > different numerical values.  For example, X1 would be the % in
> one
> > > zone, and X2 is the percent in another zone.
> > >
> > > Is there anything wrong w/ this logic?
> > >
> > >
> > > y1=alpha1+beta1(P)+e
> > > y2= alpha2 +beta2(P)+v
> > >
> > > To obtain the aggregate effect one would sum:
> > >
> > > y1+y2=(alpha1+alpha2) +(beta1+beta2)P+(e+v)
> > >
> > > Is there anything wrong with the above logic?
> > >
> > > Tam
> > >
> > > Tam
> > > *
> > > *   For searches and help try:
> > > *   http://www.stata.com/support/faqs/res/findit.html
> > > *   http://www.stata.com/support/statalist/faq
> > > *   http://www.ats.ucla.edu/stat/stata/
> > >
> >
> >
> > -----------------------------------------
> > Maarten L. Buis
> > Department of Social Research Methodology
> > Vrije Universiteit Amsterdam
> > Boelelaan 1081
> > 1081 HV Amsterdam
> > The Netherlands
> >
> > Buitenveldertselaan 3 (Metropolitan), room Z434
> >
> > +31 20 5986715
> >
> > http://home.fsw.vu.nl/m.buis/
> > -----------------------------------------
> >
> >
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> >
> *
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>

-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands

Buitenveldertselaan 3 (Metropolitan), room Z434

+31 20 5986715

http://home.fsw.vu.nl/m.buis/
-----------------------------------------

___________________________________________________________
Yahoo! For Good helps you make a difference

http://uk.promotions.yahoo.com/forgood/
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
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*   http://www.ats.ucla.edu/stat/stata/
```