Finite mixture models for proportions

Brooks, Stephen P., Morgan, Byron J. T., Ridout, Martin S., Pack, S.E. (1997) Finite mixture models for proportions. Biometrics, 53 (3). pp. 1097-1115. ISSN 0006-341X. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)

Abstract

Six data sets recording fetal control mortality in mouse litters are presented. The data are clearly overdispersed, and a standard approach would be to describe the data by means of a beta-binomial model or to use quasi-likelihood methods. For five of the examples, we show that the beta-binomial model provides a reasonable description but that the fit can be significantly improved by using a mixture of a beta-binomial model with a binomial distribution. This mixture provides two alternative solutions, in one of which the binomial component indicates a high probability of death but is selected infrequently; this accounts for outlying litters with high mortality. The influence of the outliers on the beta-binomial fits is also demonstrated. The location and nature of the two main maxima to the likelihood are investigated through profile log-likelihoods. Comparisons are made with the performance of finite mixtures of binomial distributions.

Item Type: Article
Depositing User: T. Nasir
Date Deposited: 28 Oct 2009 18:19 UTC
Last Modified: 28 May 2019 13:56 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/18310 (The current URI for this page, for reference purposes)
  • Depositors only (login required):