Statistics is the science whereby inferences are made about specific random phenomena on the basis of relatively limited sample material. The field of statistics can be subdivided into two main areas: mathematical statistics and applied statistics. Mathematical statistics concerns the development of new methods of statistical inference and requires detailed knowledge of basic mathematics for its implementation. Applied statistics concerns the application of the methods of mathematical statistics to specific subject areas such as economics, psychology and public health. Biostatistics is a branch of applied statistics that concerns the application of statistical methods to medical and biological problems. Nowadays much concern is devoted to hospital utility statistics, audit, resource allocation, vaccination uptake, incidence and prevalence of different diseases, assessment of drugs and medical diagnostic tests. Bio-statistical methods help us to analyze the obtained data from different researches, such as clinical trials, systematic reviews, genetic and proteomics surveys, and epidemiologic studies.