Compound Multinomial Likelihood Functions are Unimodal: Proof of a Conjecture of I. J. Good
复合多项分布似然函数的单峰性:证明I. J. Good的猜想
I. J. Good's 1965 conjecture of the unimodality of the likelihood function of a symmetrical compound multinomial distribution is proved by the variation-diminishing property of the Laplace transform. The result is a special case of a several sample version with asymmetrical compounding Dirichlet distributions. The technique of proof is applied to yield similar results for the negative binomial distribution and a two point mixture of Poissons.