This best selling book on medical statistics has been updated and expanded to take into account recent developments and trends in the way statistics is taught and used in medicine and has new sections on summarising qualitative data including measures such as number needed to treat, logistic regression, quasi-experimental studies, and cluster randomised trials. It uses real examples taken from current literature and is highly readable and easy-to-use. Written by two experts with wide teaching and consulting experience, the book is designed for medical students and nurses but will also be invaluable to practising doctors wishing to remind themselves of the essentials of statistical design and interpretation.