Epidemiology is the study of how health events affect communities-where, when, why and how health events occur in the context of well-defined population.
Explanation:
The 'application' of this study is for the prevention of disease and promotion of health.
It is an applied science of systematic collection, interpretation and analysis of data.
Originally, 'epidemiology' was concerned with 'epidemics and communicable diseases' but recently it is concerned with not just diseases but also all health related events.
