This book is designed for laboratory workers and clinicians, but it will also be useful for other health care professionals. The authors assume the reader has access to statistical software, so the book is not like an automobile engineer's manual, explaining in detail how statistical calculations work. Rather, it is like a road map, an itinerary, and a highway code, making it simple to travel from the starting point (definition of the question), through collection and validation of data and its analysis using the best statistical program, to the destination (interpretation of the results). The authors make liberal use of diagrams, but use equations and symbols only sparingly. The book's first section describes different kinds of data and the statistical analyses that can be applied to them. The second section deals with inaccuracy, imprecision, detection limits, analytical goals and other aspects of analytical methods, and explains how to compare both quantitative and qualitative analytical methods. The third section describes how to obtain and use data for diagnosis and for monitoring patients. The fourth section deals with study design, analysis, and reporting in medical research.