Regression analysis is a statistical method used to understand the relationship between variables. It helps in predicting the value of a dependent variable based on one or more independent variables. For example, it can be used to predict a person's weight based on their height and age, providing valuable insights in fields like economics and healthcare. The most common type of regression analysis is linear regression, which assumes a straight-line relationship between the variables. By fitting a line to the data points, analysts can make informed predictions and decisions, making regression analysis a powerful tool in data analysis and forecasting.