Epidemiology and biostatistics helps to keep up-to-date record about the prevalence of diseases within the population. It helps in the prevention of spreading disease across the world. It prohibits the diseases from becoming endemic and finally epidemic. It also helps to analyze the cause of the disease and thus helps to prevent the disease very effectively.
Biological data exhibit considerable variation in their response to stimuli. Biostatistics is particularly concerned with disentangling these different sources of variation. It seeks to distinguish between correlation and causation, and to make valid inferences from known samples about the populations from which they were drawn.