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.
@article{1176343741,
author = {Levin, Bruce and Reeds, James},
title = {Compound Multinomial Likelihood Functions are Unimodal: Proof of a Conjecture of I. J. Good},
journal = {Ann. Statist.},
volume = {5},
number = {1},
year = {1977},
pages = { 79-87},
language = {en},
url = {http://dml.mathdoc.fr/item/1176343741}
}
Levin, Bruce; Reeds, James. Compound Multinomial Likelihood Functions are Unimodal: Proof of a Conjecture of I. J. Good. Ann. Statist., Tome 5 (1977) no. 1, pp. 79-87. http://gdmltest.u-ga.fr/item/1176343741/