Stable convergence of the log-likelihood ratio to a mixture of infinitely divisible distributions

Some results concerning the asymptotic behavior of the log-likelihood ratio (LLR) and also of certain other random variables closely associated with the likelihood ratio are presented. More specifically, in the present paper we formulate the conditions for the stable convergence in distribution of the LLR for two sequences of the probability measures to a mixture of infinitely divisible distributions with finite variance. Moreover, the notion of a locally asymptotically mixed infinitely divisible (LAMID) sequence of parametric families of the probability measures is introduced, and it is shown that when a certain kind of differentiability-type regularity condition is satisfied, the given sequence of families satisfies the LAMID condition. These results extend and supplement the previous investigations of the author concerning non-Gaussian asymptotic distributions in statistics. Proceedings of the XVII Seminar on Stability Problems for Stochastic Models, Kazan, Russia, 1995, Part III.