[R] Analyzing dissimilarity ratings with Multidimensional Scaling

[Mike Marchywka]

________________________________
> Date: Mon, 14 Feb 2011 17:55:50 +0100
> Subject: Re: [R] Analyzing dissimilarity ratings with Multidimensional
> Scaling
> From: turchet.luca at gmail.com
> To: marchywka at hotmail.com
> CC: r-help at r-project.org
>
> Dear Mike,
> thanks a lot for your answer. Unfortunately the way you kindly
> suggested is not suitable
> to solve my problem.
>
> Indeed as said, I need to display the distances between the proposed trials,
> for example I would like to see a 2D plot where I can see how fare is the
> trial MT-MT from the trial MT-SW (that is how far are the evaluations of the
> audio-visual trial with metal-metal from the trial with metal-snow)

I thought the dendrogram is what you wanted but apparently you can just
use daisy perhaps. This had a lot of typos and may not run as last example
I sent had bad edits but this does create scatterplot with zero points on
diagonal etc. Presumably you can define your own functions appropriate for
your data ( I've never used some of this before which is why I'm trying,
cavear emptor).

library("cluster")
ddm<-daisy(matrix(xm,6,6),metric="euclidean")
str(ddm)
library("scatterplot3d")
dasm<-as.matrix(ddm);
nddf<-reshape(data.frame(dasm),varying=c("X1","X2","X3","X4","X5","X6"),v.name="time", direction="long")
str(nddf)
ij<-as.numeric(gl(6,6))
n2<-cbind(nddf,ij)
str(n2)
scatterplot3d(n2$ij,n2$id,n2$time,type="h")




>
> Does anyone have any other suggestion to build such perceptual map in R?
>
> In addition, how can I get some information regarding the significant
> differences
> between the trials?
> If I used the ANOVA would be simple to get those p-values. I wonder if
> it is the
> case to use it...
>
> Help!
>
>
> Luca
>
>
>
>
> On Mon, Feb 14, 2011 at 3:23 PM, Mike Marchywka
> > wrote:
>
>
>
> > My first goal in the analysis process is to print a perceptual map where to
> > place the pairs of
> > audio-visual stimuli (e.g. WD-WD, MT-DL, etc.) and see how far the trials
> > are from each other.
>
> I've been using heatmap for stuff like this.
> You can get a nice picture this way and get quick visual
> survey and dendrograms,
>
> xm<-scan(file="avm.txt")
> str(xm)
> heatmap(xm)
> heatmap(matrix(xm,6,6))
>
> I ran the above on your data and it visually looks
> like there could be interesting patterns to test.
>
>
>
>
>
>
>
>
>
> --
> ---------------------------------------------------------------
>
> "Music is a moral law:
> It gives a soul to the Universe,
> wings to the mind,
> flight to the imagination,
> a charm to sadness,
> and life to everything.
> It is the essence of order,
> and leads to all that is good,
> just and beautiful,
> of which it is the invisible,
> but nevertheless dazzling,
> passionate, and eternal form".
>
> Plato, 400 B.C. (from the Dialogues)
>