Scientific Research Publishing

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53676#.VM8uXyzQrzE Author(s)     Aloy Chijioke Onyeka , Chinyeaka Hostensia Izunobi , Iheanyi Sylvester Iwueze Affiliation(s) Department of Statistics, Federal University of Technology, Owerri, Nigeria . ABSTRACT The study proposes, along the line of [1], six separate-type estimators for estimating the population ratio of two variables in post-stratified sampling, using variable transformation. Properties of the proposed estimators were obtained up to first order approximations, both for achieved sample configurations (conditional argument) and over repeated samples of fixed size n (unconditional argument). Efficiency conditions, under which the proposed separate-type estimators would perform better than the associated customary separate-type estimators in terms of having smaller mean squared errors, were obtained. Furthermore, conditions under w...

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53360#.VMBeeSzQrzE Author(s)    Aloy Chijioke Onyeka , Chinyeaka Hostensia Izunobi , Iheanyi Sylvester Iwueze Affiliation(s) Department of Statistics, Federal University of Technology, Owerri, Nigeria . ABSTRACT Extending the work carried out by [1], this paper proposes six combined-type estimators of population ratio of two variables in post-stratified sampling scheme, using variable transformation. Properties of the proposed estimators were obtained up to first order approximations,( on <span "="">– 1 ), both for achieved sample configurations (conditional argument) and over repeated samples of fixed size n (unconditional argument). Efficiency conditions were obtained. Under these conditions the proposed combined-type estimators would perform better than the associated customary combined-type estimator. Furthermore, optimum estimators among the...

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53360#.VL3P6SzQrzE Author(s)    Aloy Chijioke Onyeka , Chinyeaka Hostensia Izunobi , Iheanyi Sylvester Iwueze Affiliation(s) Department of Statistics, Federal University of Technology, Owerri, Nigeria . ABSTRACT Extending the work carried out by [1], this paper proposes six combined-type estimators of population ratio of two variables in post-stratified sampling scheme, using variable transformation. Properties of the proposed estimators were obtained up to first order approximations,( on <span "="">–1 ), both for achieved sample configurations (conditional argument) and over repeated samples of fixed size n (unconditional argument). Efficiency conditions were obtained. Under these conditions the proposed combined-type estimators would perform better than the associated customary combined-type estimator. Furthermore, optimum estimators among the ...

Read full paper at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=50989#.VFHP-VfHRK0 Author(s) Everline Chemutai Tum , John Kung’u , Leo Odongo Affiliation(s) Department of Statistics and Actuarial Science, Kenyatta University, Nairobi, Kenya . ABSTRACT In this paper, we have proposed an estimator of finite population mean using a new regression type estimator with two auxiliary variables for single-phase sampling and investigated its finite sample properties. An empirical study has been carried out to compare the performance of the proposed estimator with the existing estimators that utilize auxiliary variables for finite population mean. It has been found that the new regression type estima...