© 1975 by Biometrika Trust
The variance of a linear combination of independent estimators using estimated weights
Educational Testing Service Princeton
Department of Applied Statistics, University of Minnesota Twin Cities
Consider k independent unbiased estimators of a common parameter
. Let t* be the linear combination of the k estimators with minimum variance, and let t
be any linear combination whose weights sum to unity and are independent of the k estimators. Then t
is unbiased for
and the variance of t
depends only on the variance of t* and the mean squared error of the weights as estimates of the optimum weights.
Key Words: Combining information Linear combination of estimators Weighted mean