1. Department of Biostatistics; University of Kansas Medical Center; Kansas City KS 66160 U.S.A.
2. P. Mean Consulting; Leawood KS 66224 U.S.A.
3. Department of Biomedical and Health Informatics; University of Missouri-Kansas City; Kansas City MO 64110 U.S.A.
4. The University of Kansas Cancer Center; Kansas City KS 66160 U.S.A.
5. School of Nursing; University of Kansas Medical Center; Kansas City KS 66160 U.S.A.