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RE: st: AW: confidence interval of a ratio of coefficients
From
Rodolphe Desbordes <[email protected]>
To
"'[email protected]'" <[email protected]>
Subject
RE: st: AW: confidence interval of a ratio of coefficients
Date
Fri, 9 Apr 2010 16:34:09 +0100
Oops... the "qui" are of course unnecessary...
Rodolphe
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Rodolphe Desbordes
Sent: vendredi 9 avril 2010 16:26
To: '[email protected]'
Subject: RE: st: AW: confidence interval of a ratio of coefficients
Martin and Nick,
Very true:
***
sysuse auto, clear
set seed 2940688
logit foreign price weight rep78
preserve
drawnorm b1-b4, n(20000) means(e(b)) cov(e(V)) clear
gen ratio=-(b2)/(b1)
qui sum ratio,meanonly
dis "ratio: " r(mean)
qui _pctile ratio, p(2.5,97.5)
dis "ll: " r(r1)
dis "ul: " r(r2)
restore
***
Rodolphe
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Nick Cox
Sent: vendredi 9 avril 2010 16:17
To: [email protected]
Subject: RE: st: AW: confidence interval of a ratio of coefficients
Even for another purpose, using -egen- to create a variable containing a
single mean is hideously inefficient. Use -su, meanonly- and pick up
r(mean) afterwards.
Nick
[email protected]
Rodolphe Desbordes
Some leftover from another code. It is useless in that code.
Martin Weiss
What is your -egen- line good for?
Rodolphe Desbordes
Would this approach make sense?
sysuse auto, clear
set seed 2940688
logit foreign price weight rep78
preserve
drawnorm b1-b4, n(20000) means(e(b)) cov(e(V)) clear
gen ratio=-(b2)/(b1)
egen mean=mean(ratio)
_pctile ratio, p(2.5,97.5)
gen ll=r(r1)
gen ul= r(r2)
sum ratio ll ul
restore
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