Yes, you catch my thought completely. A solution I used is to enumerate all
combination of A, B and C to obtain all possible values of (A-B)/(A-C) and
also enumerate all combination of D and E to get all possible D/E, then
apply Wilcoxon-Mann-Whitney rank test to compare these two groups of values.
By this method, if the lengths of A,B,..,E are 5, then we will have
5x5x5=125 values of (A-B)/(A-C) and  5x5=25 values of D/E. Such
enumerated data may inflate the sample size and make the test more
significant than the true. I don't know does it reasonable?

-Weibo



On Tue, Aug 24, 2010 at 4:41 PM, Moshe Olshansky <m_olshansky@yahoo.com>wrote:

> Do you mean that A,B,...,E are same length and you want to apply t-test to
> compare
> (A-B)/(A-C) to D/E?
> Technically this is straightforward, but even if A,B,...,E are normally
> distributed, this is very much not true for (A-B)/(A-C) and D/E, so it won't
> be appropriate to apply t-test (uness A,C and E are constants).
>
>
> --- On *Tue, 24/8/10, Weibo Xie <xwbmail@gmail.com>* wrote:
>
>
> From: Weibo Xie <xwbmail@gmail.com>
> Subject: Re: [BioC] Five variables, ABCDE, how to check whether (A-B)/(A-C)
> is equal to D/E?
> To: "Moshe Olshansky" <m_olshansky@yahoo.com>
> Cc: "Bioconductor" <bioconductor@stat.math.ethz.ch>
> Received: Tuesday, 24 August, 2010, 6:09 PM
>
>
>
> Thanks for your quick reply! I think it's like 'equal means' in Two-Sample
> t-Test.
>
>  -Weibo
>
> On Tue, Aug 24, 2010 at 3:58 PM, Moshe Olshansky <m_olshansky@yahoo.com<http://mc/compose?to=m_olshansky@yahoo.com>
> > wrote:
>
> What exactly do you mean by "equal"?
>
> --- On Tue, 24/8/10, Weibo Xie <xwbmail@gmail.com<http://mc/compose?to=xwbmail@gmail.com>>
> wrote:
>
> > From: Weibo Xie <xwbmail@gmail.com<http://mc/compose?to=xwbmail@gmail.com>
> >
> > Subject: [BioC] Five variables, ABCDE, how to check whether (A-B)/(A-C)
> is equal to D/E?
> > To: "Bioconductor" <bioconductor@stat.math.ethz.ch<http://mc/compose?to=bioconductor@stat.math.ethz.ch>
> >
> > Received: Tuesday, 24 August, 2010, 5:45 PM
> > Hello everyone,
> >
> > I have 5 variables, denoted as A to E, each with several
> > replicates. Is
> > there a reasonable statistical test to check whether
> > (A-B)/(A-C) is equal to
> > D/E?
> >
> > Thanks for your help,
> >
> > -Weibo
> >
> >     [[alternative HTML version deleted]]
> >
> > _______________________________________________
> > Bioconductor mailing list
> > Bioconductor@stat.math.ethz.ch<http://mc/compose?to=Bioconductor@stat.math.ethz.ch>
> > https://stat.ethz.ch/mailman/listinfo/bioconductor
> > Search the archives:
> http://news.gmane.org/gmane.science.biology.informatics.conductor
> >
>
>
>

	[[alternative HTML version deleted]]

