was discussed
by the author (cf. [4]) when the CV is known, and a certain linear unbiased (LU) estimator was
explored. But there is a lacuna in the given estimator by Khan or linear minimum mean square
(LMMS) estimator given by Gleser and Healy.[2] This will be clarified a bit more in the sequel.
Therefore, the main reason for revisiting this problem is to find some more efficient estimators,
and compare them with the maximum likelihood estimator (MLE).
Before pointing out the deficiencies in LU and LMMS estimators,