This book guides readers with some basic knowledge of statistics from an elementary introduction of regression analysis to advanced applications in survey research and longitudinal analysis. Emphasis is on interpretation of parameter estimates in population health and clinical research. Real life examples are explained in fuller detail than is common in most statistics books. Theory and application are presented simultaneously in a way that arouses mathematical reasoning in an intuitive context. Protocols to SAS, Stata, and R, in the form of summary tables, are employed throughout. There are extensive examples and exercises that promote understanding and reinforce the skills previously explained. An author-maintained web site includes additional commentary, selected solutions to problems in the book and further software explanations.