Empirical Bayes Estimation with Convergence Rates in Noncontinuous Lebesgue Exponential Families
Singh, R. S.
Ann. Statist., Tome 4 (1976) no. 1, p. 431-439 / Harvested from Project Euclid
Empirical Bayes estimators, asymptotically optimal with rates, are proposed. In the component problem there is a pair $(X, \omega)$ of real valued random variables. The Lebesgue density of $X$, conditional on $\omega$, is of the form $u(x)C(\omega)e^{\omega x}$. Based on a realization of $X$, the problem is squared error loss estimation of $\omega$. Let $G$ be a prior distribution on $\omega$, and $R(G)$ be the Bayes optimal risk wrt $G$. Using $(X_1, \cdots, X_n)$, the observations in the past $n$ such problems, mean square consistent estimators of the derivative of $\log (\int C(\omega)e^{\omega x} dG(\omega))$ are proposed. Then these statistics and the present observation $X$ are used to exhibit estimators $\psi_n$ for the present problem whose risks $R_n$ converge to the Bayes optimal risk $R(G)$ as $n \rightarrow \infty$. In particular, with no assumption on the smoothness or on the form of $u$, a $\psi_n$ for each $\gamma$ in [0, 2) is exhibited. Sufficient conditions are given under which $c_1n^{-4/(4+3\gamma)} \leqq R_n - R(G) \leqq c_2n^{-2\gamma/(4+3\gamma)}$, where $c_1$ and $c_2$ are positive constants. The rhs inequality holds uniformly in $G$ with support in a bounded interval of the real line, while the other holds for a $G$ degenerate at a point and for all $n$ sufficiently large. (Thus with $\gamma$ close to $2, \psi_n$ achieves almost the exact rate.) Examples of families, including one whose $u$ function has infinitely many discontinuities, are given where conditions for the above inequalities are satisfied for $\gamma$ arbitrarily close to 2.
Publié le : 1976-03-14
Classification:  Empirical Bayes estimation,  squared error loss,  convergence rates,  asymptotically optimal,  62F10,  62F15,  62C25
@article{1176343422,
     author = {Singh, R. S.},
     title = {Empirical Bayes Estimation with Convergence Rates in Noncontinuous Lebesgue Exponential Families},
     journal = {Ann. Statist.},
     volume = {4},
     number = {1},
     year = {1976},
     pages = { 431-439},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1176343422}
}
Singh, R. S. Empirical Bayes Estimation with Convergence Rates in Noncontinuous Lebesgue Exponential Families. Ann. Statist., Tome 4 (1976) no. 1, pp.  431-439. http://gdmltest.u-ga.fr/item/1176343422/