Tomas wrote:
I have aggregated data:
year X sex X age X education level X labor force participation
(7x2x9x4x2)
these data are from the whole population and I would like to make
random sample from them, but they are to big to do that, do you
have any idea how I can do that?
what I did: I use STATA 9.1/SE and first of all I changed my
memory to 950m after that I transformed aggregated data to
individual data by
expand f
it consumed a lot of time but it was ok
after that I tried to do random sample to have at each table 1000
respondents
bsample 1000, strata(year sex age)
I left the computer to work on it during the weekend but it is
not completed yet, so I think that it is not possible to do,
do you have any idea how to do random sample if I have so big data?
-----------------------------------------------------------------
I am not sure whether you can avoid the expansion, but some other advice:
1.
. compress
before expand may (or may not) reduce the size of your dataset.
2.
As suggested by Stas Kolenikov, drop any variables not needed.
3.
I guess that you by choosing 950m forced the computer to use virtual
memory which makes it very slow. See chapter 6 in [U] and this FAQ:
FAQ . . . . . . . . . . . . . . . Using a dataset that won't fit into RAM
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. Riley
1/96 How can I use a dataset that is larger than the available RAM?
http://www.stata.com/support/faqs/data/large.html
Good luck,
Svend
________________________________________________________
Svend Juul
Institut for Folkesundhed, Afdeling for Epidemiologi
(Institute of Public Health, Department of Epidemiology)
Vennelyst Boulevard 6
DK-8000 Aarhus C, Denmark
Phone, work: +45 8942 6090
Phone, home: +45 8693 7796
Fax: +45 8613 1580
E-mail: [email protected]
_________________________________________________________
*
* 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/
