Abdelmonem Afifi, Ph.D., has been Professor of Biostatistics in the School of Public Health, University of California, Los Angeles (UCLA) since 1965, and served as the Dean of the School from 1985 until 2000. His research includes multivariate and multilevel data analysis, handling missing observations in regression and discriminant analyses, meta-analysis, and model selection. Over the years, he taught well-attended courses in biostatistics for Public Health students and clinical research physicians, and doctoral-level courses in multivariate statistics and multilevel modeling. He has authored many publications in statistics and health related fields, including two widely used books (with multiple editions) on multivariate analysis. He received several prestigious awards for excellence in teaching and research. Susanne May, Ph.D., is a Professor in the Department of Biostatistics at the University of Washington in Seattle. Her areas of expertise and interest include clinical trials, survival analysis, and longitudinal data analysis. She has more than 20 years of experience as a statistical collaborator and consultant on health related research projects. In addition to a number of methodological and applied publications, she is a coauthor (with Drs. Hosmer and Lemeshow) of Applied Survival Analysis: Regression Modeling of Time-to-Event Data. Dr. May has taught courses on introductory statistics, clinical trials, and survival analysis. Robin A. Donatello, Dr. P.H., is an Associate Professor in the Department of Mathematics and Statistics and the Developer of the Data Science Initiative at California State University, Chico. Her areas of interest include applied research in the Public Health and Natural Science fields. She has expertise in data visualization, techniques to address missing and erroneous data, implementing reproducible research workflows, computational statistics and Data Science. Dr. Donatello teaches undergraduate and graduate level courses in statistical programming, applied statistics, and data science. Virginia A. Clark, Ph. D., was professor emerita of Biostatistics and Biomathematics at UCLA. For 27 years, she taught courses in multivariate analysis and survival analysis, among others. In addition to this book, she is coauthor of four books on survival analysis, linear models and analysis of variance, and survey research as well as an introductory book on biostatistics. She published extensively in statistical and health science journals.