Affiliation: | 1. Department of Statistics , University of Calcutta , 35 Ballygunge Circular Road, Kolkata , 700 019 , India ubstat@caluniv.ac.in;3. Applied Statistics Unit, Indian Statistical Institute , 203 B.T. Road, Kolkata , 700 108 , India;4. Department of Statistics , Behala College , Kolkata , 700 060 , India |