Re: st: Paired proportions- power calculation

["b. water" <barleywater@hotmail.com>]

Andrew,

I do not know how to do it in Stata. Maybe it can be done (with or without 
ease), maybe not. In the past when I have to do power calculations on paired 
proportions - I used a software called power and precision. The manual that 
comes with the trial version (the 7 days trial version allows for 10 
calculations) also included the formulas, which, I supposed, if you are 
proficient in Stata you can use adapt it to Stata. Here's the link to the 
trial version of the software:

http://www.poweranalysis.com/

Apologies to other Statalisters for listing or suggesting non-Stata related 
software. I adopt a pragmatic approach to this issue in my working life. 
Although I am learning Stata, in the meantime, if I came across a problem 
that I know can be better handled by other software (perhaps due to my 
shortcoming in Stata) then I'll used that software in the interim - to save 
time and effort. Till such time I can use Stata for that problem. Imho. Hope 
this helps.

cheers,
bw



> From: "Andrew McIntosh" <andrew.mcintosh@ed.ac.uk>
> Reply-To: statalist@hsphsun2.harvard.edu
> To: <statalist@hsphsun2.harvard.edu>
> Subject: st: Paired proportions- power calculation
> Date: Mon, 25 Aug 2003 21:13:48 +0100
>
> Hello
> I (will) have a sample of 30 pairs of people and I want to calculate the
>
> power to detect a difference of 5, 10, or 15 events between the two
> (paired ) groups, assuming the control group have an event rate of about
> 50%.
>
> Unforunately, the 'sampsi' command doesn't seem to extend to matched
> pairs and I wondered if there was a method of completing this
> analysis using another STATA command? Thank you for any help...
>
> Andrew McIntosh, Edinburgh University
>
>
>
>
>
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