ok, I'll do it tomorrow, as soon I as I will have access to my office's
computer where the data are saved.
Thank you
Mariarosaria
Citazione Nick Cox <[email protected]>:
> I think we need to see some precise evidence of
> what you think is problematic. Thus, we need to
> see _exactly_ what you typed and _exactly_ what
> Stata did -- as the FAQ advises.
>
> Nick
> [email protected]
>
> [email protected]
>
> > thank you for your answers,
> > evidently my question was not clear:
> > I am aware that STATA does not drop missing observations when
> > using the
> > regress command, it just does not use them, but I expect the
> > same regression
> > sample:
> > if I drop the missing observations before the regression as
> > if I just run the regression without dropping missing values...
> > thus, I don't understand why stata runs the regression on
> > different samples
> > when I use the two commands described before
>
> Maarten buis
>
> > > --- [email protected] wrote:
> > > > when I use the following command:
> > > > drop if x>450
> > > > STATA drops a lot of observations, while when I exclude missing
> > > > values as follows:
> > > > drop if x>450 & x!=.
> > > > STATA eliminates just a couple of observations
> > >
> > > This is well known behaviour: In Stata missing values are
> > the largest
> > > possible values, so a missing value will be larger than
> > 450. As result
> > > if you type -drop if x>450- the missing values will also be dropped.
> > >
> > > > I realized this when I run a regression including x as
> > regressor. If
> > > > STATA drops missing data with the first command,
> > shouldn't drop the
> > > > same observations when I run the regression after using the second
> > > > command?
> > >
> > > I don't think I understand the question. Do you think that -regress-
> > > should influence the way -drop- behaves?
>
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