7.20 The data of Exercise 3.3 describe the number of dead fetuses in litters of mice. This is one of six data sets considered by Brooks et al. (1997). Brooks

(2001) has analysed these data from a Bayesian perspective and considered five alternative models for each data set, viz., a beta-binomial model, a mixture of two binomials, a mixture of a binomial and a beta-binomial, a mixture of three binomials and a mixture of two beta-binomials. Shown below are his posterior model probabilities. The coding used for the data sets is the same as that used in Brooks et al. (1997), and data set E1 is the data presented in Exercise 3.3. BBin denotes beta-binomial, etc.