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Re: st: Re: R: Minimal Detectable Difference


From   William Buchanan <william@williambuchanan.net>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   Re: st: Re: R: Minimal Detectable Difference
Date   Tue, 5 Jun 2012 06:33:05 -0700

Hi Lars,

It may not be Stata, but you could also take a look at G*Power.  It's free and can be used to calculate various aspects of statistical power (e.g., required sample size to detect a given effect size, minimum detectable effect size, etc...).  It doesn't calculate these sizes for SEM or MLM, but for most other models you can get quick and easy answers.

- Billy

Sent from my iPhone

On Jun 5, 2012, at 5:41, Lars Folkestad <lfolkestad@health.sdu.dk> wrote:

> That is what i ended up doing. But i hoped there was a nicer/smerter/more
> standardized way to do it.
> lars
> 
> Den 05/06/12 14.06 skrev "carlo.lazzaro@tiscalinet.it"
> <carlo.lazzaro@tiscalinet.it>:
> 
>> 
>> 
>> 
>> Lars can probably simulate some scenarios with -sampsi-. I find this
>> approach particularly useful when the limited number of participants
>> available is due to budget constraints (as it is often the case, sadly).
>> Kindest Regards,
>> Carlo
>> 
>> 
>> -----Messaggio originale-----
>> Da: owner-statalist@hsphsun2.harvard.edu
>> [mailto:owner-statalist@hsphsun2.harvard.edu] Per conto di Lars Folkestad
>> Inviato: martedì 5 giugno 2012 13:39
>> A: statalist@hsphsun2.harvard.edu
>> Oggetto: st: Minimal Detectable Difference
>> 
>> Dear List
>> 
>> This might be a bit more of a stats question than a stata question.
>> 
>> I am about to do a cross sectional study comparing two groups regarding a
>> measured continous variable.
>> I know the the variance of the measurement. No one has ever investigated
>> these groups before using this or similar machines. For practical reasons
>> i
>> only have a limited number of participants available for this project. I
>> am
>> now wondering what the minimal detectable difference between the two
>> groups
>> are with the number of participants i have available.
>> 
>> I will use a t-test (paired, seeing the two groups are matched)
>> 
>> How do i calculate this using stata?
>> 
>> lars
>> 
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>> 
> 
> 
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