Saeid Tahmasebi

In this paper, a new sampling method is introduced by ordering the maxima of ranked set samples with unequal sizes. In this new modification of ranked set sampling which is called OMRSSU, the pdf, cdf and joint pdf are obtained. Also, a new distribution-free prediction interval for future order statistics is derived. In addition, the moments of OMRSSU for exponential distribution are computed and then the best linear unbiased estimators of exponential distribution are obtained using OMRSSU. Finally, a comparison is made between BLUE-OMRSSU and the BLUE based on ranked set sampling, ordered ranked set sampling, maximum ranked set sampling and order statistics from a simple random sample.