1. Hovav A. Dror is recent Ph.D. graduate and David M. Steinberg is Professor , Department of Statistics and Operations Research, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Israel. The authors thank the referees and an associate editor for their helpful comments. They also thank Benny Yoskovich and Yehoshua Borkowsky for letting them try the method at IMI.