Proportion

Epidemiology is the underlying and basic science of public health. It could be defined as any research of health events in populations, including: how many are affected by such events, is the risk increasing or decreasing, what is the relevance of the problem and how could it be prevented.

The term 'personalised medicine' includes both stratification and personalisation, which are often incorrectly used as synonyms. However, the two are different, as explained further below.

Statistics play an important role in clinical trials in preventing errors, biases, and false inferrences. This article covers some key statistical concepts, such as hypothesis testing, type 1 and type 2 errors, and the difference between correllation and causation.