Affiliation: | 1.Department of Mathematics and Statistics, University of North Carolina at Charlotte, Fretwell 335L, 9201 University City Blvd., Charlotte, NC, 28223, USA ;2.Department of Biostatistics, University of North Carolina at Chapel Hill, 3101D McGavran-Greenberg Hall, Chapel Hill, NC, 27599, USA ;3.Department of Biostatistics, University of North Carolina at Chapel Hill, 3104C McGavran-Greenberg Hall, Chapel Hill, NC, 27599, USA ; |