1. Department of Statistics; University of South Carolina; Columbia, South Carolina 29208 U.S.A.
2. Department of Mathematical Sciences; Clemson University; Clemson, South Carolina 29634 U.S.A.
3. Department of Biostatistics; University of North Carolina at Chapel Hill; Chapel Hill, North Carolina 27599 U.S.A.
4. Department of Health Services Policy and Management; University of South Carolina; Columbia, South Carolina 29208 U.S.A.