ghazi shukur Högskolan i Jönköping   Dept. of economics and statistics P. O. Box 1026, Högskolan i Jönköping , SE- 551 11 Sweden   ghazi.shukur@ihh.hj.se   http://www.ihh.hj.se           JEL Areas: C1 : Econometric and Statistical Methods: General C3 : Multiple or Simultaneous Equation Models: General