1971/08/01 by James V. Zidek · 3 citations
Mathematics · Decision Sciences · #Statistical Methods and Inference #Probability and Risk Models
paper · pdf · doi:10.1214/aoms/1177693258
Suppose that independent normally distributed random vectors Wn× 1 and Tk× 1 are observed with E(W) = 0, E(T) = μ, Cov (W) = σ2 I and Cov (T) = σ2 I. In this paper it is shown that each member of a certain class of estimators of μ + ησ for a given vector η is inadmissible if loss is dimension-free quadratic loss. This class includes the best invariant estimator. The proof is carried out by exhibiting, for each member, θ, of the class, an estimator depending on θ whose risk is uniformly smaller than that of θ.