On geometry of the set of admissible invariant quadratic estimators in balanced two variance components model.

Two variance components model for which each invariant quadratic admissible estimator of a linear function of variance components (under quadratic loss function) is a linear combination of two quadratic forms, Z₁, Z₂, say, is considered. A set D = {(d₁, d₂)' : d₁Z₁ + d₂Z₂ is admissible} is described by giving formulae on the boundary of D. Different forms of the set D are presented on figures. [ABSTRACT FROM AUTHOR]