NEW RATIO ESTIMATORS OF THE MEAN USING SIMPLE RANDOM SAMPLING AND RANKED SET SAMPLING METHODS

In this paper, modified ratio estimators of the population mean of the variable of interest are suggested involving the first orthird quartiles of an auxiliary variable that is correlated with the variable of interest. The newly suggested estimators areinvestigated under simple random sampling (SRS) and ranked set sampling (RSS) methods. It is found that these estimatorsare approximately unbiased and the RSS estimators are more efficient than those based on SRS method for the same quartileand sample size. Also, it is found that, when the two quartiles are compared, estimators based on the third quartile are moreefficient than the first quartile.