- Regression analysis is used to study the relationship between variables and predict how the value of one variable changes with the other. It is one of the most commonly used tools for business analysis. - Simple linear regression analyzes the relationship between one independent variable and one dependent variable. The regression equation estimates the dependent variable as a linear function of the independent variable. - Least squares regression fits a line to the data by minimizing the sum of the squared residuals, providing estimates of the slope and y-intercept coefficients in the regression equation.