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A new approximation of the posterior distribution of the log–odds ratio
Author(s) -
Fredette Marc,
Angers Jean–François
Publication year - 2002
Publication title -
statistica neerlandica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 39
eISSN - 1467-9574
pISSN - 0039-0402
DOI - 10.1111/1467-9574.t01-1-00057
Subject(s) - dirichlet distribution , mathematics , multinomial distribution , distribution (mathematics) , posterior probability , concentration parameter , statistics , mathematical analysis , bayesian probability , boundary value problem
In this paper, the posterior density of the log–odds ratio is studied. It is assumed that the observations have a multinomial distribution and that the prior on the multinomial parameters is a Dirichlet density. Several approximations currently available are reviewed. Under certain conditions on the prior parameters of the Dirichlet density, it is shown that the posterior moments can be computed exactly. A new approximation, similar to the Edgeworth expansion is also proposed. Using a numerical example, the different methods of approximation of posterior density are compared.