Questions regarding collections of parameter estimates can frequently
be expressed in terms of an empirical mixing distribution (EMD). This
report discusses empirical Bayes estimation of an EMD, with emphasis o
n the construction of interval estimates. Estimation of the EMD is acc
omplished by substitution of estimates of prior parameters in the post
erior mean of the EMD. This procedure is examined in a parametric mode
l (the normal-normal mixture) and in a semi-parametric model. In both
cases, the empirical Bayes bootstrap of Laird and Louis (1987, Journal
of the American Statistical Association 82, 739-757) is used to asses
s the variability of the estimated EMD arising from the estimation of
prior parameters. The proposed methods are applied to a meta-analysis
of population trend estimates for groups of birds.