Adel Boughrara Department of Quantitative Methods, University of Sousse   IHEC of Sousse B.P. 40 Route de la ceinture Sahloul III Sousse, 4054 TUNISIA   adel.boughrara@gmail.com             JEL Areas: C5 : Econometric Modeling: General E5 : Monetary Policy, Central Banking, and the Supply of Money and Credit: General