Ranked set sampling method was proposed by McIntyre (1952) to estimate mean pasture yields. Recently, RSS was developed and modified by many authors to estimate the population parameters. Dell and Clutter (1972) showed that the mean of the RSS is an unbiased estimator of the population mean, whether or not there are errors in ranking. Muttlak (1997) suggested using median ranked set sampling (MRSS) to estimate the population mean. Al-Saleh and Al-Omari (2002) suggested multistage ranked set sampling (MSRSS) in order to increase the efficiency of estimating the population mean specific value of the sample size. Jemain and Al-Omari (2006) suggested double quartile ranked set sampling (DQRSS) for estimating the population mean. Jemain and Al-Omari (2007) have extended DQRSS to multistage quartile ranked set sampling (MQRSS) for estimating the population mean and they showed that the efficiency of the mean estimator using MQRSS can be increased for specific value of the sample size m by increase the number of stages.Also see Al-Omari and Jaber (2008), Bouza (2002), Al-Nasser (2007) and Ohyama et al. (2008) for further information on ranked set sampling.
In this paper, stratified median ranked set sampling (SMRSS) is suggested for estimating the population mean. The paper is organized as follows: In Section 2 we describe several sampling methods considered in this study. Estimation of the population mean is given in Section 3. In Section 4, a simulation study is conducted to investigate the performance of the suggested methods. Finally, conclusions are given in Section 5.