similar to: Summary : Whitehead's group sequential procedures

Dear List, I would like to know if there exist some R implementation of John Whitehead's procedures for the planning and analysis of group sequential clinical trials. His book is enlightenig but somewhat frustrating : it has a good basic exposition of his framework, but the technical details are sparse, and leave much work to do when one plans to reuimplement part of the procedures. For

Hello Everyone,   I’m a SAS user who has recently become interested in sequential clinical trials designs. I’ve discovered that the SAS based approaches for these designs are either too costly or are “experimental.” So now I’m looking for alternative software. Two programs that seem promising are SPLUS Seqtrial and R.   I recently obtained a 30 day trial for the SPLUS Seqtrial add-on and have

Hello R users, I am looking for R (or S) code related to group sequential or adaptive designs for clinical trials. (The most prominent examples are the designs of Pocock or O'Brien/Fleming, the alpha-spending function approach, or Fisher's combination test and the inverse normal method.) I am particularly interested in the calculation of the critical boundaries, the handling of spending

Hello everyone, I need to do a sample size calculation. The study two arms and two endpoints. The two arms are two different cancer drugs and the two endpoints reflect efficacy (based on progression free survival) and toxicity. Until now, I have been trying to understand this in terms of a one-arm design, where the acceptable rate of efficacy might be 0.40, the unacceptable rate of efficacy

[my original message to s-news & r-help is attached ] No one possessed or knew of any S/R code for the sequential t-test. Also it doesn't appear in the SAS index. One or two suggested obtaining the S+ seqtrial software which may (or may not) cover this, but this seemed to be a bit of a "hammer to crack a nut". I have written a function based on the treatment in Wetheril

Following up to some extent on Friday's discussion regarding the 'validation' of R, could I ask the list group's opinion on possible advantages of R over Splus from a pharma/devices perspective? I wish to exclude the obvious price difference, which doesn’t seem to carry as much weight as I would have thought. Besides, I have noticed many former Splus users gravitating towards R,

Hello List: Please find uploaded to CRAN a new package, PwrGSD The package is intended for the design and analysis of group sequential trials There are two main functions, (1) GrpSeqBnds: computes group sequential stopping boundaries for interim analysis of a sequential trial based upon a normally distributed test statistic. This can be done via the Lan-Demets procedure with

Hello List: Please find uploaded to CRAN a new package, PwrGSD The package is intended for the design and analysis of group sequential trials There are two main functions, (1) GrpSeqBnds: computes group sequential stopping boundaries for interim analysis of a sequential trial based upon a normally distributed test statistic. This can be done via the Lan-Demets procedure with

Has anyone tried to download Hmisc and used ldBands function for calculating Lan-Demets group sequential boundaries? The write-up in F.Harrell's website indicates that, besides downloading the package Hmisc, one needs to copy the progra ld98 from the University of Wisconsin website. As suggested, I did this but received another error message regarding the search path. I think I have fixed

I'm trying to get dovecot running on my VPS and the main imap process is receiving a SIGKILL from what I presume to be the Linux Kernel and/or OpenVZ. This happens after I login and my client(s) just sit their idling. The mailbox is empty. I'm not running out of memory. stracing the process doesn't show anything interesting... ... gettimeofday({1233024777, 844804}, {420, 0}) = 0

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(Yes, today is the "John has an idea day") So, in my now fairly extensive coding of extension priority lists, I'm getting very bored of re-numbering my priority lists every time I add something at the top of the list. If I have a 7 step priority list, and I need to add something in at priority 2, then I have to re-number five other priorities, and if my Dial statement is

Andreas was kind enough to point out that not neccesarily all ext3fs have htrees ready to go. I am running redhat8.0 out of the box. How can I check if ext3fs with htrees is running? I can download the kernel source, but I don't know what options were used when it was built by redhat. Thanks much for all of your help. -Parker -----Original Message----- From: Andreas Dilger

Didn't hear back from anyone regarding if there is a way to determine if I am running the ext3fs with htree. Is there a way I can do it without checking the src code since I am running the precompired redhat kernel with 8.0? Perhaps an entry under /proc somewhere? Pj -----Original Message----- From: Parker Johnson Sent: Tuesday, January 14, 2003 3:34 PM To: 'Andreas Dilger';

Bummer. Does anyone have a url that describes the 2.4 patching process? Any claims on stability? Thanks, Parker -----Original Message----- From: 'Andreas Dilger' [mailto:adilger@clusterfs.com] Sent: Wednesday, January 15, 2003 4:35 PM To: Parker Johnson Cc: 'ext3-users@redhat.com'; Ops Subject: Re: ext3fs still uses sequential search of file names in director ies? On Jan 15,

Instead of using sequential integers for IDs for my objects I was wondering if I could easily make it so that my IDs where longer auto- generated random strings/integers. So instead of: http://www.mydomain.com/user/view/1 Would be: http://www.mydomain.com/user/view/d81096b87a7c5565f On top of that... is there big benefits for security reasons to use non-sequential numbers? Is it worth

Dear Listers, If I have several glm objects with names glm1, glm2.... and want to apply new data to these objects. Instead of typing "predict(glm1, newdata)..." 100 times, is there way I could do so in a loop? Thank you so much! wensui [[alternative HTML version deleted]]

After the (remote) delete action for my lesson_categories controller i fall through to this js.rjs file: page.visual_effect :fade, "lesson_category_#{@lesson_category.id}", :duration => 1 page.remove "lesson_category_#{@lesson_category.id}" The problem, though, is that the visual effect is initiated, then the remove is initiated, before the visual effect is finished, so

Yesterday I posted the following question to the help list. Thanks to John Fox (copied below) who pointed out the solution. Original question: I have come across a result that I cannot explain, and am hopingthat someone else can provide an answer. A student fitted a mixed model usingthe lme function: out<- lme(fixed=Y~A+B+A:B, random=~1|Site). Y is a continuous variable while A and

Hi there, I want to find the adjusted confidence intervals in group sequential trials in a simulation setting. GroupSeq provides me with what I am looking for in an interactive setting, but I am not sure how to make it work in a simulation setting so that it produces a series of adjusted confidence intervals for a series of Z-statistics that I provide it without me having to enter each