Hiroaki Masuhara Department of Health Services Management, Hiroshima International University   1-5 Nobori-cho Naka-ku Hiroshima-shi, Hiroshima 730-0016 Japan   h-masuha@hw.hirokoku-u.ac.jp             JEL Areas: C3 : Multiple or Simultaneous Equation Models: General C1 : Econometric and Statistical Methods: General