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Re: st: Errors in egen, total()
Hi Mike,
my guess it that it's a rounding problem because of different data
types. I was able to reproduce your problem in section B below. Try to
declare your cumrev-variable to be long instead of floating point (C).
---Beginning example:---
preserve
*A: Both float
input str1 title week rev
A 707 28536717
A 708 10
A 708 20
end
bys title week: egen cumrev=total(rev)
format rev cumrev %9.0f
list
*B: Rev long, cumrev float
clear
input str1 title week long rev
A 707 28536717
A 708 10
A 708 20
end
bys title week: egen cumrev=total(rev)
format rev cumrev %9.0f
list
*C: Both long
clear
input str1 title week long rev
A 707 28536717
A 708 10
A 708 20
end
bys title week: egen long cumrev=total(rev)
format rev cumrev %9.0f
list
restore
---End example---
Type 'help data_types' for more information.
Cheers,
Sven-Oliver
On Sun, Dec 13, 2009 at 05:19, Mike Kim <[email protected]> wrote:
> Hello all,
>
> I used "egen total()" to create "cumrev" like the following, but if there is
> only one week per title, total gives a slightly lower number than the
> original number in some cases (1 or 2 lower). Any idea about why it produces
> different numbers?
>
> bys title week: egen cumrev=total(rev)
>
> title week rev cumrev
> A 707 28536717 28536716
> A 708 10 30
> A 708 20 30
> B 801 .....
> ......
>
> Thank you,
> Mike.
>
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