Charles Whiteman The University of Iowa   Department of Economics The University of Iowa W380 PBB Iowa City, IA 52242 USA   whiteman@BLUE.WEEG.UIOWA.EDU   http://www.biz.uiowa.edu/faculty/cwhiteman/index.html           JEL Areas: C1 : Econometric and Statistical Methods: General C5 : Econometric Modeling: General