During the last twenty years statistical methodology has become of central importance in research studies in medicine and also in day-to-day clinical practice. The medical literature is now liberally punctuated not only with relatively routine statistical terms such as p-value, t-test, confidence interval, and correlation, but also with more esoteric items such as hazard function, multilevel model, generalized estimating equations and crossover design. Consequently researchers in medicine and clinicians who are not primarily statisticians need to have a source that provides readable accounts...