Zahoor Ahmad, an Assistant Professor and Head of the Statistics Department at the University of Gujrat, completed his PhD in Statistics under the supervision of Professor Muhammad Hanif from the National College of Business Administration and Economics, Lahore, Pakistan, and recently completed his Post-Doctoral Fellowship with Professor Danny Pfeffermann from the University of Southampton, UK. He has more than 15 publications to his name and most of these are in the area of parameter estimation using multi-auxiliary information with and without nonresponse. His areas of interest include survey sampling, statistical computing and complex survey modeling. Muhammad Qaiser Shahbaz is currently working as Professor of Statistics and the Head of the Statistics Department at COMSATS Institute of IT, Lahore. He has more than 70 research publications to his credit. His core area of research is sampling with unequal probabilities but he has also published research papers in the areas of mathematical statistics and distribution theory. Further areas of interest include survey sampling, statistical models, computer applications in statistics and medical statistics.Muhammad Hanif is working as Professor of Statistics and Vice Rector (research) at the National College of Business Administration and Economics, Lahore. His main field of research is model and design based survey sampling. He has published more than 150 research papers in various international journals and is the author of more than ten books. He has supervised over 40 PhD theses in various fields including survey sampling, bio-statistics, community and family medicine, public health and medicine.