First Author:   Ozlem Goktas Istanbul University, Faculty of Economics, Department of Econometrics ozlemg@istanbul.edu.tr   Istanbul University, Faculty of Economics, Department of Econometrics, Beyazit Istanbul, 34452, Turkey   +90 212 440 01 60(Phone) +90 212 440 01 60(Fax) Second Author: Aycan Hepsag Istanbul University, Faculty of Economics, Department of Econometrics hepsag@istanbul.edu.tr   Istanbul University, Faculty of Economics, Department of Econometrics, Beyazit Istanbul, 34452, Turkey   +90 212 440 01 60(Phone) +90 212 440 01 59(Fax)