About the Author: Evdokia Xekalaki, Department of Statistics, Athens University of Economics and BusinessProfessor Xekalaki has been teaching for nearly 30 years, and in that time has held such positions as Director of the graduate program, consultant to EUROSTAT and twice Chair of the Dept of Statistics at AUEB. She has published more than 50 papers in numerous international journals and has presented papers at many international conferences. She is also the Chief Editor of the journal Quality Technology and Quantitative Management and on the Editorial Board for the Journal of Applied Stochastic Models in Business and Industry. Stavros Degiannakis, Department of Statistics, Athens University of Economics and BusinessAdjunct lecturer in applied econometrics, Dr Degiannakis acquired his PhD last year, and has already had eight articles published in seven journals, and eight other papers presented at a variety of international conferences.