Parametric convergence rate of some nonparametric estimators in mixtures of power series distributions

Fuente: arXiv
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Autori principali: Balabdaoui, Fadoua, Besdziek, Harald, Wang, Yong
Natura: Preprint
Pubblicazione: 2025
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author Balabdaoui, Fadoua
Besdziek, Harald
Wang, Yong
author_facet Balabdaoui, Fadoua
Besdziek, Harald
Wang, Yong
contents We consider the problem of estimating a mixture of power series distributions with infinite support, to which belong very well-known models such as Poisson, Geometric, Logarithmic or Negative Binomial probability mass functions. We consider the nonparametric maximum likelihood estimator (NPMLE) and show that, under very mild assumptions, it converges to the true mixture distribution $π_0$ at a rate no slower than $(\log n)^{3/2} n^{-1/2}$ in the Hellinger distance. Recent work on minimax lower bounds suggests that the logarithmic factor in the obtained Hellinger rate of convergence can not be improved, at least for mixtures of Poisson distributions. Furthermore, we construct nonparametric estimators that are based on the NPMLE and show that they converge to $π_0$ at the parametric rate $n^{-1/2}$ in the $\ell_p$-norm ($p \in [1, \infty]$ or $p \in [2, \infty])$: The weighted least squares and hybrid estimators. Simulations and a real data application are considered to assess the performance of all estimators we study in this paper and illustrate the practical aspect of the theory. The simulations results show that the NPMLE has the best performance in the Hellinger, $\ell_1$ and $\ell_2$ distances in all scenarios. Finally, to construct confidence intervals of the true mixture probability mass function, both the nonparametric and parametric bootstrap procedures are considered. Their performances are compared with respect to the coverage and length of the resulting intervals.
format Preprint
id arxiv_https___arxiv_org_abs_2508_00163
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Parametric convergence rate of some nonparametric estimators in mixtures of power series distributions
Balabdaoui, Fadoua
Besdziek, Harald
Wang, Yong
Statistics Theory
62G20
We consider the problem of estimating a mixture of power series distributions with infinite support, to which belong very well-known models such as Poisson, Geometric, Logarithmic or Negative Binomial probability mass functions. We consider the nonparametric maximum likelihood estimator (NPMLE) and show that, under very mild assumptions, it converges to the true mixture distribution $π_0$ at a rate no slower than $(\log n)^{3/2} n^{-1/2}$ in the Hellinger distance. Recent work on minimax lower bounds suggests that the logarithmic factor in the obtained Hellinger rate of convergence can not be improved, at least for mixtures of Poisson distributions. Furthermore, we construct nonparametric estimators that are based on the NPMLE and show that they converge to $π_0$ at the parametric rate $n^{-1/2}$ in the $\ell_p$-norm ($p \in [1, \infty]$ or $p \in [2, \infty])$: The weighted least squares and hybrid estimators. Simulations and a real data application are considered to assess the performance of all estimators we study in this paper and illustrate the practical aspect of the theory. The simulations results show that the NPMLE has the best performance in the Hellinger, $\ell_1$ and $\ell_2$ distances in all scenarios. Finally, to construct confidence intervals of the true mixture probability mass function, both the nonparametric and parametric bootstrap procedures are considered. Their performances are compared with respect to the coverage and length of the resulting intervals.
title Parametric convergence rate of some nonparametric estimators in mixtures of power series distributions
topic Statistics Theory
62G20
url https://arxiv.org/abs/2508.00163