1. Department of Economics and Informatics, Federal Rural University of Pernambuco, Serra Talhada, PE 56909-535, Brazil
2. Department of Statistics and Informatics, Federal Rural University of Pernambuco, Recife, PE 52171-900, Brazil
3. Independent Research, Brazil
4. Federal Institute of Education, Science and Technology of Paraíba, Campus Patos, PB., Acesso rodovia PB 110, S/N Alto Tubiba - CEP: 58700-030, PB, Patos, Brazil