<>
Try this with no warranty :-)
I do have a feeling there is some command, like moving average or -rolling-,
that can make this a little more elegant...
**
clear*
set obs 51
gen year=_n+1949
expand 100
gen byte category=irecode(runiform(), /*
*/ 0, .08, .16, .24, .32, .4, .48, /*
*/ .54, .62, .68, .78, .89 )
compress
capture erase info.dta
tempname hdle
postfile `hdle' year /*
*/ category mean /*
*/ using info
levelsof category, local(mycats)
qui forv y=1952/1998{
foreach cat of local mycats{
cou if inrange(year, `y'-3, `y'+3) & /*
*/ category==`cat'
post `hdle' (`y') (`cat') (`r(N)')
}
}
postclose `hdle'
u info, clear
gen lb=y-3
gen ub=y+3
order lb year ub /*
*/ category mean
l, noobs sepby(year) h(30)
**
HTH
Martin
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Nirina F
Sent: Mittwoch, 21. Oktober 2009 23:05
To: [email protected]
Subject: st: How to generate this variable please?
Dear all,
I am not even sure how to search in the help for this so I thought I
would ask you.
I have two variables year (1950 to 2000) and field. Field has
different categories 1 for accounting, 2 for art 3 for biochemistry
etc....until 12.
I would like to have a variable that shows the mean of the frequency
in accounting (category 1) for year -3 and +3. To be more explicit:
for example, I studied in 1955. I would like to attribute to myself
the average frequency of people who did accounting between 1952 and
1958 so that it will be an indicator for me on how popular accounting
was around 1955. For year 1950, we can just look at +3, for year 2000,
we can just look at -3 years.
I am confused myself so I hope you understand what I mean.
then I would like to do it for category 5 and 6 together of variable Field.
Thank you so very much in advance for your help,
Nirina
*
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*
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* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
