Katherine E. Irimata is a mathematical statistician at the National Center for Health Statistics* in the Division of Research and Methodology. Brittany N. Dugger is an assistant professor of pathology and laboratory medicine at the University of California, Davis, where she is the neuropathology core coleader at the Alzheimer's Disease Center. Jeffrey R. Wilson is an associate professor of statistics and biostatistics at Arizona State University. He is the coauthor of Modeling Binary Correlated Responses using SAS, SPSS and R and the coeditor of Innovative Statistical Methods for Public Health Data. *Katherine E. Irimata is serving in her personal capacity, and the work for this book was initiated and conducted when she was a student at Arizona State University. The views expressed are those of the authors and do not necessarily represent the views of the National Center for Health Statistics, the Centers for Disease Control and Prevention, or the US government.