Regression models are statistical tools used to understand the relationship between a dependent variable and one or more independent variables. They help predict outcomes by fitting a line or curve to the data points, allowing us to see how changes in the independent variables affect the dependent variable. There are various types of regression models, including linear regression, which assumes a straight-line relationship, and multiple regression, which involves multiple independent variables. These models are widely used in fields like economics, biology, and social sciences to analyze trends and make informed decisions based on data.