Re: st: obtain SD from P value for a paired t-test

[Marcos Vinicius <bioestatistico@inbox.com>]

Thanks Rich but not solved yet.
I know the N,so I can get the standard deviation of the diference(post-pre).
However I still don t know if it is possible to obtain the standard deviation corresponding to the post measure.
Vinicius
> -----Original Message-----
> From: richgold@ix.netcom.com
> Sent: Tue, 01 Oct 2013 13:04:47 -0400
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: obtain SD from P value for a paired t-test
> 
> if you know N also, you can use the formula given in the Stata manual
> (methods and formulas section of the ttest entry in the reference
> manual), or many texts, to get the sd - if you don't know N, the best
> you can do is an approximation
> 
> Rich
> 
> On 10/1/13 12:09 PM, Marcos Vinicius wrote:
>> Hello,
>> Anyone knows a way to obtain  standard deviation(sd) from P value for a
>> paired t-test.?
>> Consider that I know:
>> Average pre
>> SD pre
>> Average post
>> SD post (to be determined from others parameters)
>> P value from paired t test
>> 
>> Average pre=6.5
>> SD pre=1.8
>> Average post =4.9
>> SD post ??(to be determined from others parameters)
>> P value from paired t test p=0.0003
>>  Any help would be greatly appreciated
>> Thanks
>> Vinicius
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