Statistical Theory is a branch of mathematics that deals with the collection, analysis, interpretation, and presentation of data. It provides the framework for making inferences about populations based on sample data, using concepts such as probability, estimation, and hypothesis testing. This theory is essential in various fields, including economics, psychology, and medicine, as it helps researchers draw conclusions and make decisions based on empirical evidence. Key components include descriptive statistics, which summarize data, and inferential statistics, which allow predictions and generalizations about larger groups.