In this paper we study the asymptotic behaviour of the posterior distribution in a mixture model when the number of components in the mixture is larger than the true number of components, a situation commonly referred to as overfitted mixture. We prove in particular that quite generally the posterior distribution has a stable and interesting behaviour, since it tends to empty the extra components. This stability is achieved under some restriction on the prior, which can be used as a guideline for choosing the prior. Some simulations are presented to illustrate this behaviour.
Publié le : 2011-07-05
Classification:
Asymptotic,
Bayesian,
mixture models,
overfitting,
posterior concentration,
[MATH.MATH-ST]Mathematics [math]/Statistics [math.ST],
[STAT.TH]Statistics [stat]/Statistics Theory [stat.TH]
@article{hal-00641475,
author = {Rousseau, Judith and Mengersen, Kerrie},
title = {Asymptotic behaviour of the posterior distribution in overfitted mixture models},
journal = {HAL},
volume = {2011},
number = {0},
year = {2011},
language = {en},
url = {http://dml.mathdoc.fr/item/hal-00641475}
}
Rousseau, Judith; Mengersen, Kerrie. Asymptotic behaviour of the posterior distribution in overfitted mixture models. HAL, Tome 2011 (2011) no. 0, . http://gdmltest.u-ga.fr/item/hal-00641475/