A regression problem has an output variable or dependent variable. This is a real value, such as weight, age, or any other real numbers. We discussed regression in detail in Chapter 9, Hypothesis Testing and Regression, including the different types of regression (simple linear regression, multiple linear regression, and non-linear regression), and used the Boston Housing dataset to perform regression analysis. 

Since we discussed regression problems in Chapter 9, Hypothesis Testing and Regression, we are going to move on and learn more about the classification problem.