ABSTRACT
Epidemiology, as the designation indicates, began as the study of epidemics. Over time it transformed into the field that pervades all aspects of clinical medicine. It is common now for departments in medical schools to be called “Epidemiology and Biostatistics”, a label that makes clear the significant statistical nature of its activities. This field has imported or developed a number of statistical measures for manipulating data. We now turn to a number of these epidemiological measures, which will be referred to at various points in subsequent chapters.
