Sorry it didn 't work again. I am on yahoo mail, and just found a switch to
change from Rick text to Plain text, so 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:
> library(gsDesign)
> 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: Jeff Newmiller <jdnew...@dcn.davis.ca.us>
oject.org>; Berend Hasselman <b...@xs4all.nl>
Cc: R-help Mailing List <r-help@r-project.org>
Sent: Sunday, September 24, 2017 12:41 AM
Subject: Re: [R] gsDesign Pocock & OBF boundary
Still failed.
The first secret is in your email program settings, to use Plain Text format
(at least for emails you send to this mailing list).
The second secret tool to use is the reprex package to let you verify that your
code example will do on our computers what it is doing on your computer before
you send it to us. That will also involve giving us some sample data or
referencing some data already available to us in a relevant package. See [1],
[2] and [3] for more discussion of how to succeed at communicating on the
Internet regarding R.
[1]
http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example
[2] http://adv-r.had.co.nz/Reproducibility.html
[3] https://cran.r-project.org/web/packages/reprex/index.html (read the
vignette)
--
Sent from my phone. Please excuse my brevity.
On September 23, 2017 9:53:05 PM PDT, array chip via R-help
<r-help@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 <b...@xs4all.nl>
>Cc: R-help Mailing List <r-help@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@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]
>
>> ______________________________________________
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>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.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
