[R-sig-eco] help

[Sarah Goslee]

Hi,

On Fri, Dec 9, 2011 at 7:13 AM, Mahnaz Rabbaniha <rab.mahnaz at gmail.com> wrote:
> Hi
>
> in my project i collected its data in excel sheet that i attached,data
> were non normal then i transformed them and check the normality by
> shapiro.test that it showed again non-normality therefore i decided
> used the MDS analyses in r and download this site
>  ( http://www.statmethods.net/advstats/mds.html)
>
> but i haven't done it,  i think  the main problem is the form of excel
> matrix for doing it and also i want to know about different between  CLASSICAL
> MDS and isoMDS.

We need to know more about what you're donig to be able to help with
the excel matrix. What is the problem? How are you importing it into R?

?cmdscale
library(MASS)
?isoMDS

offers some information about the algorithms used in the two approaches,
as well as many references for more information

Briefly and simplistically, the difference has to do with whether the algorithm
attempts to preserve actual dissimilarities or rank-order dissimilarities.

> please help me because this method is new in iran
>
> Thanks in advance
> --
> *Mahnaz Rabbaniha*
> *Senior expert of marine ecology *
> *Iranian Fisheries Research Organization (IFRO) *
> *P.O.Box: 14155-6116 , P.Code: 1411816618*
> Tehran, IRAN
> Phone:   +98 21 44580953
> *Fax:       +98 21 44580583*
> *Mobile:  +98 912 5790377*
> *Website: http://www.ifro.ir*
>

-- 
Sarah Goslee
http://www.functionaldiversity.org