Sent from my phone. Please excuse my brevity.
On September 23, 2017 9:53:05 PM PDT, array chip via R-help <r-help at r-project.org> wrote:
>Sorry for messed up text. Here it goes again:
>I am learning to use the gsDesign package.
>I have a question about Pocock and OBF boundary. As far as I can
>understand, these 2 boundaries require equal spacing between interim
>analyses (maybe this is not correct?). But looks like I can still use
>gsDesign to run an analysis based on unequal spacing:?
>> gsDesign(k=2,test.type=2,timing=c(0.75,1),alpha=0.05,sfu='Pocock')
>Symmetric two-sided group sequential design with 90 %power and 5 % Type
>I Error.Spending computations assume trial stops if a bound is
>crossed.? ? ? ? ? Sample? ? ? ? ? Size? Analysis Ratio*? Z? Nominal p?
>Spend? ? ? ? 1? 0.796 1.82? ? 0.0346 0.0346? ? ? ? 2? 1.061 1.82? ?
>0.0346 0.0154? ? Total? ? ? ? ? ? ? ? ? ? ? 0.0500?++alpha spending:
>Pocock boundary.*Sample size ratio compared to fixed design with no
>interim?
>Can anyone share some light whether the above analysis is still valid?
>Or for unequal spacing, I have to use Lan-Demet?s error spending
>function approximations? Thank you,
>
>
>
> From: Berend Hasselman <bhh at xs4all.nl>
> To: array chip <arrayprofile at yahoo.com>
>Cc: R-help Mailing List <r-help at r-project.org>
> Sent: Friday, September 22, 2017 11:46 PM
> Subject: Re: [R] gsDesign Pocock & OBF boundary
>
>
>> On 23 Sep 2017, at 01:32, array chip via R-help
><r-help at r-project.org> wrote:
>>
>> Hi,
>>
>> I am learning to use your gsDesign package! I have a question about
>Pocock and OBF boundary. As far as Iunderstand, these 2 boundaries
>require equal spacing between interim analyses(maybe this is not
>correct?). But I can still use gsDesign to run an analysisbased on
>unequal spacing:
>gsDesign(k=2,test.type=2,timing=c(0.75,1),alpha=0.05,sfu='Pocock')Symmetrictwo-sided
>group sequential design with90 %power and 5 % Type I
>Error.Spendingcomputations assume trial stops if a bound is crossed.? ?
>? ? ? Sample? ? ? ? ? Size? AnalysisRatio*? Z? Nominal p? Spend? ? ? ?
>1? 0.796 1.82? ? 0.0346 0.0346? ? ? ? 2? 1.061 1.82? ? 0.0346 0.0154? ?
>Total? ? ? ? ? ? ? ? ? ? ? 0.0500? ++alpha
>spending:Pocockboundary.*Sample size ratio compared to fixed design
>with no interim Can anyone share some light whether the above analysis
>is stillvalid? Or for unequal spacing, I have to use Lan-Demet?s error
>spendingfunction approximations? Thank you,
>> ??? [[alternative HTML version deleted]]
>>
>
>Your example code is a complete mess.
>Do NOT post in html. This is a plain text mailing list.
>Read the Posting Guide (https://www.r-project.org/posting-guide.html).
>
>Berend Hasselman]
>
>> ______________________________________________
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>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
> [[alternative HTML version deleted]]
>
>______________________________________________
>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>PLEASE do read the posting guide
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>and provide commented, minimal, self-contained, reproducible code.