Message-ID: <XFMail.050426213255.Ted.Harding@nessie.mcc.ac.uk>
Date: 2005-04-26T20:32:55Z
From: (Ted Harding)
Subject: Finding 'ncp' for t
In-Reply-To: <x2mzrlsfwn.fsf@turmalin.kubism.ku.dk>
On 26-Apr-05 Peter Dalgaard wrote:
> (Ted Harding) <Ted.Harding at nessie.mcc.ac.uk> writes:
>
>> Hi Folks,
>>
>> I'm looking for a neat procedure for the following:
>>
>> Given t0 such that
>>
>> pt(t0,df,ncp=0) = alpha (given)
>>
>> find ncp0 such that for given beta
>>
>> pt(t0,df,ncp=ncp0) = (1 - beta)
>>
>> (In other words, what's the ncp such that you get power (1-beta)
>> to detect it, using a 1-sided test with size alpha when ncp = 0?)
>>
>> In the past I've done the groping by hand, but this time it
>> needs to be done many times over, so a good solver for ncp0
>> in this situation would be handy.
>
> You might want to peek inside power.t.test(). Or just use it...
Thanks for reminding me of this, Peter. It can be persuaded to
do what I want!
Also to Rolf Turner for his suggestion.
Best wishes,
Ted.
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E-Mail: (Ted Harding) <Ted.Harding at nessie.mcc.ac.uk>
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Date: 26-Apr-05 Time: 20:13:16
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