st: AW: AW: RE: AW: Exclude some observations from a sample in a regression

["Martin Weiss" <martin.weiss1@gmx.de>]

<> 


Do not confuse the mechanism of the -if- qualifier, which Nick told you
about, with the behavior of -regress- which throws out the observations with
missings in -rep78-. -if- does behave the way Nick said...



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Claude
Francoeur
Gesendet: Mittwoch, 7. April 2010 14:59
An: statalist@hsphsun2.harvard.edu
Betreff: st: AW: RE: AW: Exclude some observations from a sample in a
regression

Thanks for showing me these different methods. I should have mentioned 
that I do have missing values in my sample. I'm confused though 
concerning the right command to use.

regress price weight length if foreign returns a regression using 22 
observations since there are no missing cases

regress price weight length rep78 if foreign returns a regression using 
21 observations since there is one missing value under rep78. This seems 
to be contrary to Nick's comment, but I probably am missing something. 


regress price weight length rep78 if foreign==foreign returns a 
regression using all 69 non missing observations including domestic 
cases. The if command does not seem to be recognised.

Thanks for your help!













 

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