Affiliation: | 1 Department of Mathematics and Statistics, Bowling Green State University, Bowling Green, Ohio 43403-0221, U.S.Atnguyen{at}bgnet.bgsu.edu jchen{at}bgnet.bgsu.edu gupta{at}bgnet.bgsu.edu 2 Department of Statistics, US Environmental Protection Agency, Washington, DC 20460, U.S.A.dinh.khoan{at}epamail.epa.gov |