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st: Problem with Stata handling of large dataset
From
"Palan, Stefan ([email protected])" <[email protected]>
To
"[email protected]" <[email protected]>
Subject
st: Problem with Stata handling of large dataset
Date
Mon, 5 Aug 2013 15:42:10 +0200
Hi everybody,
I have noticed a problem with Stata (SE 12.1, 64 bit) when working with large datasets. When I type the following:
----------------------------------------------------------------------
clear
set obs 63000000
gen long id=_n
gen long y=int(id/5)
gen long z=int((id-1000)/5)
gen long yz=y-z
sum yz
----------------------------------------------------------------------
I get the following output:
----------------------------------------------------------------------
Variable | Obs Mean Std. Dev. Min Max
-------------+--------------------------------------------------------
yz | 63000000 200 .0035635 199 200
----------------------------------------------------------------------
Shouldn't the standard deviation be zero, and min equal max equal mean? If I type
----------------------------------------------------------------------
sum yz if yz==199
----------------------------------------------------------------------
I find that there are 800 observations where yz==199.
Can anybody help me with this problem?
Cheers,
Stefan.
Stefan Palan
Post-Doc
University of Innsbruck
Institute of Banking and Finance
Universitaetsstrasse 15/4
6020 Innsbruck
Tel.: +43 (0) 512 / 507-7579
Fax.: +43 (0) 512 / 507-2846
[email protected]
http://www.palan.biz/academic
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