Copyright 2006 Mayo Foundation for Medical Education and Research This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. For other licensing arrangements, please contact Mariza de Andrade Mariza de Andrade, Ph.D. Division of Biostatistics Mayo Clinic 200 First Street SW Rochester, MN 55905 email: mandrade@mayo.edu