ELFT HÍRADÓ

["Laszlo E. Szabo" <leszabo AT hps.elte.hu>]

Department of HISTORY AND PHILOSOPHY OF SCIENCE
Eotvos University, Budapest
Pazmany P. setany 1/A Budapest
Phone/Fax: (36-1) 372 2924
Department's Home Page:http://hps.elte.hu

Philosophy of Science Colloquium
Room 6.54 (6th floor) Monday 4:00 PM
____________________________________
18 November  4:00 PM   6th floor 6.54
Instead of the canceled lecture of 21 October!

Tamas Rudas
Department of Statistics, Institute of Sociology, Eötvös University, 
Budapest

 Measurement and modelling of association in contingency tables

Association between two variables is defined in the talk as the 
information in their joint distribution not present in the univariate 
distributions. Therefore, a measure of association, together with the 
marginal distributions, has to parameterize the joint distribution and 
has to be variationally independent from the marginals. These 
requirements point to the odds ratio as the only appropriate measure of 
association.

For higher dimensional contingency tables, a possible generalization is 
the system of conditional odds ratios. The conditional odds ratios, on 
an ascending class of subsets, are variationally independent from the 
marginal distributions on the complement descending class and together 
parameterize the joint distribution. Depending on the class of subsets 
used, one obtains a flexible class of parametereizations that can be 
used to model the conditional association structure. The models obtained 
by assuming lack of conditional association on an ascending class of 
subsets are of the log-linear type.

The concepts discussed in the talk and the analyses based on these 
concepts suggest that association has a hierarchical structure. The 
assumption of multivariate normality, routinely applied in our thinking 
about multivariate data structures, is equivalent to assuming that only
first order interactions exist is therefore, is an oversimplification of 
reality.

------------------------------------------------------------------------

The 60-minute lecture is followed by a 10-minute break. Then we held a
30-60-minute discussion.
------------------------------------------------------------------------

The organizer of the seminar: László E. Szabó
<http://hps.elte.hu/~leszabo> (email: 
leszabo AT hps.elte.hu)

--
L a s z l o   E.   S z a b o
Theoretical Physics Research Group of the Hungarian Academy of Sciences
Department of History and Philosophy of Science
Eotvos University, Budapest
H-1518 Budapest, Pf. 32, Hungary
Phone/Fax: (36-1)372-2924
Mobil/SMS: (36) 20-366-1172
http://hps.elte.hu/~leszabo