I would like to express my deep and sincere gratitude to my advisor Assist. Prof. Dr. Muhlise COŞKUN ÖGEYİK. Her wide knowledge and her logical way of thinking have been of great value for me. Her understanding, encouraging and personal guidance have provided a good basis for the present study. I wish to express my warm and sincere thanks to all of my students who have participated in the study. I am grateful to Assoc. Prof. Dr. Tolga ARICAK for his guidance in statistical analysis of this study. His kind support has been of great value for this study. My sincere thanks are due to my friends and colleagues Gökçen BAYRAK YILMAZ and Fatma ÖZKAN for their untiring help during my difficult moments and to all other colleagues in International Re...