Divulgação de seminário

[Roseli Aparecida Leandro <raleandr@carpa.ciagri.usp.br>]

Prezados colegas,

 Dando inÃcio ao Ciclo de SeminÃrios do PPG Estatistica e
ExperimentaÃÃo AgrÃnomica, ESALQ, USP, temos o prazer de
convidÃ-los para o seminÃrio:

**Poisson weighted function related to over- and underdispersion **
                    **CÃlestin C. Kokonendji**
Università de Pau et des Pays de lâAdour,  France 

Local: Sala 311, Departamento de CiÃncias Exatas, ESALQ/USP,
Piracicaba, SP
Data: 09/03/2006
HorÃrio: 16:00 h



Abstract
Consider a weighted Poisson distribution (WPD) having the  same mean
than the original Poisson distribution. This talk proves  that the
mean value of the weight function with respect to the  underlying
Poisson distribution is a logconvex (logconcave) function
 if and only if the WPD is overdispersed (underdispersed) relative to 
the Poisson distribution.The logconvexity (logconcavity) of the 
weight function is only a sufficient condition, and some other 
properties are examined. For a comprehensive relation between over-
and underdispersion, we then introduce a notion of duality between 
two WPD such that the product of their weight functions is one. Some 
illustrative examples are presented and discussed, in particular for 
practical weight functions. We conclude by a new approach for 
analyzing count data.



Cordiais saudaÃÃes,

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