ON ESTIMATING THE MEAN OF SYMMETRICAL POPULATIONS

Two classes of estimators in two different situations of (i) unknown and (ii) known variance (sigma-(2)), for estimating the population mean (mu) of symmetrical populations have been proposed. The general expressions of bias and mean squared error, of which the bias and mean squared error of other estimators considered by various authors may be easily seen to be special cases, are found. Further, subclasses of optimum estimators in the sense of having minimum mean square error are given. All the results of previous particular estimators may easily be derived as special cases of this study.