Statistics, branch of mathematics that collects, tabulates, and analyzes data by a numerical system which, in turn, is used to make predictions and projections about situations that are uncertain. The process usually involves the acquisition of data from a small group that is used to make predictions about the behavior of a larger group. For example, in a presidential campaign most candidates take polls indicating their level of popularity. These polls do not survey every person in the country, but are based on a sample from a much smaller number of people. Essential to such calculations is the theory of probability, which is utilized to judge the soundness of the numerical assumptions. Statistics plays a significant role in many areas, including scientific research, business (insurance), and politics.