تفاصيل الرسالة العلمية

In this thesis, the problem of estimating the population mean is considered using simple random sampling (SRS), ranked set sampling (RSS), and median ranked sampling (MRSS) methods. Various ratio estimators and ratio-cum-product estimators of the population mean are suggested. Also, exponentiated ratio-cum-product estimators of the population mean are proposed by using SRS, RSS and MRSS methods. The mean squared errors (MSE) and bias equations are derived and proved. The suggested estimators of the population mean are compared within themselves and with usual ratio and product estimators of the population mean mathematical and by simulation. An application of areal data set of 1083 trees is considered to study the applicability of the new estimators. It turnout that the suggested estimators of the population mean are more efficient than the usual ratio and product estimators of the population mean. Also, the proposed estimators based on RSS and MRSS are more efficient than their competitors using SRS based on the same number of measured units