Affiliation: | 1. Dept. of Economic and Social Statistics , New York State School of Industrial and Labor Relations, Cornell Univ. , Ithaca , NY , 14850 , USA;2. Dept. of Statistics and Operations Research , Wharton School, Univ. of Pennsylvania , Philadelphia , PA , 19174 , USA;3. Dept. of Statistics , Princeton Univ. , Princeton , NJ , 08540 , USA |