R help - Aug 2011 - assign group letters to T/F matrix

dear R community,

i appologize as this is kind of a newbie question, but:

I want to assign group letters (like in anova post-hoc tests) to data
with combined means and SDs. It's easy to apply t-test formulas to get
a materix like

(A - D are treatments

  |  A   B   C   D
-----------------------
A|       T    F   F
B|             T   F
C|                  F
D|

where true stands for sign. differences/ F for no sign. differences.
is there an alogarithm that converts such a matrix to letters to be
assignedto A, B, C,... ? and does maybe somebody know a packages that
runs t-tests on means+SD+n data?

lukas kohl

Have a look at package multcomp at: 
http://cran.r-project.org/package=multcomp


I hope it helps.

Best,
Dimitris


On 8/31/2011 2:30 PM, eldor ado wrote:
> dear R community,
>
> i appologize as this is kind of a newbie question, but:
>
> I want to assign group letters (like in anova post-hoc tests) to data
> with combined means and SDs. It's easy to apply t-test formulas to get
> a materix like
>
> (A - D are treatments
>
>    |  A   B   C   D
> -----------------------
> A|       T    F   F
> B|             T   F
> C|                  F
> D|
>
> where true stands for sign. differences/ F for no sign. differences.
> is there an alogarithm that converts such a matrix to letters to be
> assignedto A, B, C,... ? and does maybe somebody know a packages that
> runs t-tests on means+SD+n data?
>
> lukas kohl
>
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
>
-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
Web: http://www.erasmusmc.nl/biostatistiek/