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June 2003

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Subject:
From:
"J. Douglas Carroll" <[log in to unmask]>
Reply To:
Classification, clustering, and phylogeny estimation
Date:
Tue, 10 Jun 2003 10:09:13 -0400
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Try Analyzing Multivariate Analysis by Lattin, Carroll and Green (Duxbury,
2003).

Doug Carroll.


At 11:57 AM 6/10/2003 +0100, you wrote:
>Hi everyone,
>I have couple of questions on (hierarchical) cluster analysis and
>Multidimensional scaling. As part of my research, I collected data using a
>method called 'similarity rating' on a scale of 1 to 9. There are 30
>variables (30 concepts from physics to be exact). I want to find out how
>people organise these concepts. The software I am using is SPSS 11,
>because SPSS is the only one I know how to use and one of the two
>statistical packages available in university computers (I think the other
>one is SAS). I should add that I am not very familiar with the theoretical
>background of these analyses, though trying my best to get as much
>information as I can/need. For example, I have been reading a lot lately
>on MDS and HCA, but I still do not know what the basic assumptions are for
>MDS and HCA. I need to find a good book which explains things
>conceptually, with little mathematical notation.
>Now my real problem, as I enter the data in SPSS, I use the subjects'
>ratings of the pairwise similarities for the 30 concepts. I want to know
>which of these is the appropriate statistical analysis for my analysis. I
>am confused with the metric/non-metric distinction. My data is non-metric
>I think. Can I use HCA with non-metric data? If I can, and if HCA is
>appropriate, what is the best method? Ward's? Between-groups linkage? or
>within-groups linkage? etc. Since my original data is already a proximity
>matrix (or at least I think it is), what HCA is doing seems to be wrong.
>It tries to create proximity matrix again. Is this ok? When I run the
>analysis as it is, it seem fine, but when I change the syntax so that it
>uses the original data matrix in /MATRIX IN ('filename.sav'), a totally
>different clustering is produced. Which one is correct? Is there a clearly
>written book on multivariate analysis using SPSS?
>
>For MDS, I have similar problem. What are the things I need to do to get a
>clear picture of how people organise these 30 concepts. Because stress
>value with low dimensions is quite law, I have to increase the number of
>dimensions. By the way in SPSS results, there a lot of stress values:
>normalized raw stress, Stress-I, Stress-II and S-Stress. Which of these
>should I use to interpret my results? Also, what are "Dispersion Accounted
>For (D.A.F.)" and "Tucker's Coefficient of Congruence" used for? What is
>the difference between Simplex and Torgerson in initial configuration options?
>
>I know this is a lot, but as I mentioned earlier there isn't any book on
>multivariate statistics using SPSS as far as I know. Many books on
>multivariate statistics explain things to make life more difficult. If you
>could help me, I would be very happy.
>
>Thank you very much for your interest and help in advance.
>
>Sincerely,
>
>Ufuk YILDIRIM



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   # J. Douglas Carroll, Board of Governors Professor of Management and #
   #Psychology, Rutgers University, Graduate School of Management,      #
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