Vivek Verma, Assistant Professor, Department of Statistics, Assam University Silchar, Assam, India.Hafiz T.A. Khan, Professor of Public Health and Statistics at the University of West London and a Professorial Fellow at the Oxford Institute of Population Ageing, University of Oxford, UK. For the last three decades, he has been involved in teaching applied statistics, public health, demography, health economics and research methods. He has published more than 260 research articles in various international journals.Dilip C. Nath, Former Vice-Chancellor of Assam University and Professor of Statistics at Gauhati University, India. He has published more than 200 research papers in reputed national and international journals. His current research interests are in biostatistics, medical statistics, demography and actuarial statistics.Kenneth C. Land, John Franklin Crowell Professor Emeritus of Sociology at Duke University, where he is also a research professor at the Social Science Research Institute. He worked as faculty in the University of Illinois at Urbana-Champaign and the University of Texas at Austin and has published more than 450 research papers in various international journals.