Re: st: RE: Comparing medians with pweight

["Ada C. Chen" <ada08chen@gmail.com>]

Thanks! Roger.
The manuals of rank statistics are very helpful.

Best,

Ada

2007/3/7, Newson, Roger B <r.newson@imperial.ac.uk>:
> I don't know whether you really want to compare 2 medians or to estimate
> the median pairwise difference between 2 groups. (These are not the same
> thing, as the median pairwise difference is not always the difference
> between the 2 medians, although the mean pairwise difference is the
> difference between the 2 means.) However, if you want to estimate the
> median pairwise difference (with confidence limits), then you can use
> the -cendif- program, which is part of the -somersd- package,
> downloadable from SSC. -cendif- (unlike -median-) allows you to use
> pweights.
>
> The -somersd- package calculates confidence intervals for a range of
> rank statistics, and is distributed with 3 .pdf manuals, which you can
> download as ancillary files. You can also find more about the methods in
> Newson (2006a) and Newson (2006b), both of which have pre-publication
> drafts which you can download from my website at
> http://www.imperial.ac.uk/nhli/r.newson/
>
> I hope this helps.
>
> Best wishes
>
> Roger
>
>
> References
>
> Newson, R. 2006a.  Confidence intervals for rank statistics:  Somers' D
> and extensions.  Stata Journal 6: 309-334.
>
> Newson, R. 2006b.  Confidence intervals for rank statistics:  Percentile
> slopes, differences, and ratios.  Stata Journal 6: 497-520.
>
>
>
> Roger Newson
> Lecturer in Medical Statistics
> Respiratory Epidemiology and Public Health Group
> National Heart and Lung Institute
> Imperial College London
> Royal Brompton campus
> Room 33, Emmanuel Kaye Building
> 1B Manresa Road
> London SW3 6LR
> UNITED KINGDOM
> Tel: +44 (0)20 7352 8121 ext 3381
> Fax: +44 (0)20 7351 8322
> Email: r.newson@imperial.ac.uk
> www.imperial.ac.uk/nhli/r.newson/
>
> Opinions expressed are those of the author, not of the institution.
>
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Ada C. Chen
> Sent: 07 March 2007 17:49
> To: statalist@hsphsun2.harvard.edu
> Subject: st: Comparing medians with pweight
>
> Dear all,
>
> Is it possible to compare medians of a continuous variable between two
> groups by using -pweight- instead of -fweight-? Does stata only allow
> for fweight?
>
> Here is my code and result:
> . median income [pweight=wt1], by(priv)
> pweight not allowed
> r(101);
>
>
> Best,
>
> Ada
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