This document defines regression analysis and its key concepts. Regression analysis is used to estimate or predict an unknown dependent variable from known independent variables. There are two types of variables: dependent and independent. Linear regression establishes a linear relationship between a continuous dependent variable and one or more continuous or discrete independent variables using a best-fit straight line. The regression equation represents this relationship as Y=a+bX+e, where a is the intercept, b is the slope, and e is the error term, which can be used to predict the dependent variable based on the independent variables. An example is provided to predict the number of new students joining a school based on the percentage of students returning from the previous year.