1. Environmental Statistics Unit, Centre for Econometrics and Applied Research, Department of Statistics, University of Ibadan, Ibadan 200001, Nigeria
2. Department of Statistics, Ladoke Akintola University of Technology, Ogbomoso 212102, Nigeria
3. Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, MA 01609, USA
4. Atmospheric Physics Unit, Department of Physics, University of Ibadan, Ibadan 200132, Nigeria
5. Faculty of Economics, ICS & DATAI, University of Navarra, 31009 Pamplona, Spain
6. Faculty of Legal and Business Sciences, Universidad Francisco de Vitoria, 28223 Madrid, Spain