Department of Statistics and Applied Mathematics, Federal University of Ceará, Ceará, 60455-760, Brazil. michael@ufc.br|Department of Statistics and Applied Mathematics, Federal University of Ceará, Ceará, 60455-760, Brazil. michael@ufc.br|Department of Statistics and Applied Mathematics, Federal University of Ceará, Ceará, 60455-760, Brazil. michael@ufc.br|Department of Statistics and Applied Mathematics, Federal University of Ceará, Ceará, 60455-760, Brazil. michael@ufc.br