On Selecting a Subset Containing the Best Population-A Bayesian Approach
Goel, Prem K. ; Rubin, Herman
Ann. Statist., Tome 5 (1977) no. 1, p. 969-983 / Harvested from Project Euclid
The problem of selecting a subset of $k$ populations $\pi_1, \cdots, \pi_k,$ which contains the "best" population, is considered. The unknown values $\theta_1, \cdots, \theta_k$ are the characteristics associated with $\pi_1, \cdots, \pi_k$ and the unknown population associated with $\theta_{\lbrack k\rbrack} = \max_i\theta_i$ is called the "best." It is assumed that, given $\mathbf{\theta} = (\theta_1, \cdots, \theta_k)$ the $\operatorname{pdf}$ of the independent random variables $X_1, \cdots, X_k$ belong to a monotone likelihood ratio family, the prior distribution of $\mathbf{\theta}$ is exchangeable, and the loss function is a linear combination of two components, namely the subset size $|s|$ and the distance between the "best" and the "best" in the selected subset $s,$ i.e., $\mathbf{L}(\mathbf{\theta}, s) = c|s| + \lbrack\theta_{\lbrack k\rbrack} - \max_{j : \pi_j \in s} \theta_j\rbrack.$ It is shown that the Bayes rule depends on at most $(k - 1)$ computable expressions. Some lower and upper bounds on the differences of Bayes risks are given to help reduce the amount of computation for the Bayes rule. If $X_i$ has a normal distribution with mean $\theta_i$ and known variance $\sigma^2,$ then it is shown that (i) for $k = 2,$ the Bayes rule with vague prior knowledge and the classical rule are the same if the probability of correct selection, $P^\ast,$ is chosen as a suitable function of $c,$ and (ii) if $c/\sigma \geqq 1/\pi^\frac{1}{2},$ then the Bayes rule selects only one population and if $.2821 \leqq c/\sigma < 1/\pi^\frac{1}{2},$ then it selects at most two populations. The tables for implementing the Bayes rule for normal populations are also given.
Publié le : 1977-09-14
Classification:  Subset selection,  nonlinear loss function,  normal populations,  monotone likelihood ratio family,  exchangeable prior distribution,  Bayes rules,  62F07,  62G30
@article{1176343952,
     author = {Goel, Prem K. and Rubin, Herman},
     title = {On Selecting a Subset Containing the Best Population-A Bayesian Approach},
     journal = {Ann. Statist.},
     volume = {5},
     number = {1},
     year = {1977},
     pages = { 969-983},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1176343952}
}
Goel, Prem K.; Rubin, Herman. On Selecting a Subset Containing the Best Population-A Bayesian Approach. Ann. Statist., Tome 5 (1977) no. 1, pp.  969-983. http://gdmltest.u-ga.fr/item/1176343952/