Statistical Papers DOI 10.1007/s00362-007-0079-y REGULAR ARTICLE Ratio estimator for the population mean using ranked set sampling Cem Kadilar · Yesim Unyazici · Hulya Cingi Received: 20 February 2006 / Revised: 4 June 2007 © Springer-Verlag 2007 Abstract We adapt the ratio estimation using ranked set sampling, suggested by Samawi and Muttlak (Biometr J 38:753–764, 1996), to the ratio estimator for the pop- ulation mean, based on Prasad (Commun Stat Theory Methods 18:379–392, 1989), in simple random sampling. Theoretically, we show that the proposed ratio estimator for the population mean is more efficient than the ratio estimator, in Prasad (1989), in all conditions. In addition, we support this theoretical result with the aid of a numerical example. Keywords Ratio estimator · Ranked set sampling · Simple random sampling · Efficiency Mathematics Subject Classification (2000) 62D05 1 Introduction The traditional ratio estimator for the population mean _ Y of the study variable y is defined by _ y r = _ y _ x _ X = ˆ R _ X (1) in which it is assumed that the population mean _ X of the auxiliary variable x is known. Here _ y is the sample mean of the study variable and _ x is the sample mean of the auxiliary variable. C. Kadilar (B ) · Y. Unyazici · H. Cingi Department of Statistics, Hacettepe University, Beytepe, 06800 Ankara, Turkey e-mail: kadilar@hacettepe.edu.tr 123