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Re: st: sample size reduced significantly
From
Nick Cox <[email protected]>
To
"[email protected]" <[email protected]>
Subject
Re: st: sample size reduced significantly
Date
Fri, 12 Apr 2013 00:36:46 +0100
Values must be non-missing for all variables entered in a regression;
otherwise observations will be excluded. After your regression
. regress <whatever>
You can identify the excluded values
. gen excluded = !e(sample)
and then look for missings in the excluded
. egen nmissing = rowmiss(<whatever>) if excluded
. tab nmissing
Here <whatever> is whatever varlist you used for -regress-.
Nick
[email protected]
On 11 April 2013 21:16, Yu Chen, PhD <[email protected]> wrote:
> I have several variables with each of them having at least 6000
> observations (non-missing values). However, when I put them into OLS
> regression, the number of observations reduced to only about 1000. I
> cannot figure out what causes the problem. Could you please help me
> find out the causes? What code can I use to analyze the problem?
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