Prayad Sangngam. (2014) Modified Ratio Estimators in Stratified Random Sampling. <i>Journal of SCIENCE and TECHNOLOGY Mahasarakham University</i>, <i>33</i>(2), 112-116.Prayad Sangngam. "Modified Ratio Estimators in Stratified Random Sampling". Journal of SCIENCE and TECHNOLOGY Mahasarakham University 33 (2014):112-116.Prayad Sangngam. Modified Ratio Estimators in Stratified Random Sampling. Mahasarakham University:ม.ป.ท. 2014.