1. Department of Mathematics and Statistical Sciences, Botswana International University of Science and Technology, Palapye, Botswana
2. Department of Mathematics and Statistics, University of South Alabama, Mobile, AL, USA
3. Mathematics and Statistics, Auburn University, Auburn, AL, USA
4. Harvard Data Science Initiative, Harvard University, Cambridge, MA, USA
5. Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA