avviso seminario

[Pietro Muliere <pietro.muliere@uni-bocconi.it>]

Istituto Metodi Quantitativi - Università L. Bocconi
Viale Isonzo, 25 - 20135 Milano
Tel. 02-58365629  - Fax 02-58365630


SEMINARIO



  A New Bayesian method
for Nonparametric Capture-recapture Models
in Presence of Heterogeneity


Luca Tardella

Dipartimento di Statistica, Probabilità e Statistiche Applicate
Università di Roma “La Sapienza”




Giovedi', 22 febbraio 2001 - ore 16.00
aula IMQ - stanza 137

____________________________________________________________________
Abstract
Capture-recapture models are among the oldest and most popular methods for 
estimating how large a wild animal population is, though usefulness of 
these models goes beyond zoological matters having been applied, among 
others, to epidemiologic studies, socio-demographic investigations and even 
to software reliability problems.
The intrinsic heterogeneity of individuals has been soon recognized as a 
potential source of severe bias in the estimation procedures. To account 
for this heterogeneity in the model a hierarchical structure has been 
proposed where the probabilities that each animal is caught in a single 
occasion are modeled as i.i.d. draws from a common unknown distribution F. 
 From the article by Burnham and Overton (1978) there has been general 
agreement on the fact that modeling F with a parametric curve is not 
satisfactory. Henceforth many nonparametric solutions have been developed 
for instance (Smith and van Belle 1984); Chao (1989); (Norris and Pollock 
1996).
Recently a Bayesian solution has been also provided that makes use of a 
Dirichlet process prior for F (Basu 1998). Here we suggest an alternative 
Bayesian approach that relies on a different parameterizations which still 
maintains no assumptions on the shape of F but drives the problem back to a 
finite-dimensional setting. Applications of the new methodology to computer 
simulated data as well as on-field simulations and other real data sets are 
provided.



=================================================================

       Forum per la Societa' Italiana di Statistica

                       AVVERTENZA

     il nuovo servizio viene offerto in via sperimentale
     dal Dipartimento di Scienze Statistiche di Perugia
           con il software Majordomo 1.94.5
       istallato su una Workstation UNIX (AIX 4.3.3)

           Ci scusiamo per eventuali disguidi !

=================================================================