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RE: Re: st: RE: AW: ratio function


From   "Roman Kasal" <kasal@trexima.cz>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: Re: st: RE: AW: ratio function
Date   Fri, 2 Apr 2010 08:46:41 +0200

I don't agree...so how to do it when you want to find out ratio between
years, male X female, ...? So there is no solution? Just to keep N,mean,
SE, degrees of freedom, N_strata, N_psu, .... and calculate it manually?
I think it is not appropriate solution, at least to have it as an
option. I think there is missing a lot with complex survey in Stata and
complex survey is needed for almost every survey research, even freeware
R-project is better equipped :(

so have a hope Stata will get it soon....immediately we are buying it
again :)

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Steven
Samuels
Sent: Thu, 1 Apr 2010 09:30:10 -0400
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: RE: AW: ratio function

And it should.   Data (x,y) (1,2) (2,4) (3,6) (100,.)    will give an
entirely different view of the data if the unpaired observation is
included in a mean or ratio calculation.  Or consider data with x
missing in half the pairs and y missing in the other half; the ratio
of means would be meaningless.

The formulas for standard errors for ratios  assume that the data are
paired. Formally, they are based on the residual MSE of a regression
of y on x through the origin. You cannot do that regression with
unpaired data.

If your concern is missing data, the solution is to impute the missing
values before analysis.

Steve

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Roman Kasal

> but it ignores unpaired data :(

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