--- On Tue, 18/8/09, John Hund wrote:
> As an example, I have data (sales and ages) on firms by
> year in different industries. I would like to find the
> age of the firm with the median value on sales for each
> year and industry.
*---------- begin example --------------
clear
input ///
age sales ind year id
2 1.04 3339 1991 1
3 1.75 3339 1991 2
3 3.08 3339 1991 3
31 .496 3339 1991 4
42 .546 3339 1991 5
42 1.5 3339 1991 6
5 . 3411 1991 7
8 .584 3411 1991 8
30 .491 3411 1991 9
19 .944 3411 1991 10
20 .692 3411 1991 11
28 1.81 3411 1991 12
29 .601 3411 1991 13
32 .509 3411 1991 14
42 .938 3411 1991 15
42 .886 3411 1991 16
end
gen byte miss = missing(age, sales, ind, year)
bysort miss ind year (sales): gen long n = ///
_N - 1 if miss == 0
bysort miss ind year (sales): gen medage = ///
(age[`= floor(n/2)'] + age[`= ceil(n/2)'])/2 ///
if miss == 0
drop miss n
list
*--------------- end example ----------------------
Hope this helps,
Maarten
-----------------------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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