This document provides an introduction to regression analysis. It defines regression analysis as measuring the average relationship between two or more variables in their original units. Regression analysis is used to predict the values of dependent variables from independent variables. There are three main types of regression analysis: simple and multiple regression analyze one or two variables, linear regression uses a straight line model while non-linear regression does not, and total regression considers all important variables while partial regression excludes some. Graphic and algebraic methods can be used to study regression, with the graphic method using scatter diagrams and the algebraic deriving equations.