## 35.1 Introduction

In the last chapter, correlation was studied, which measures the strength of the linear relationship between two quantitative variables $$x$$ and $$y$$. We now study regression, which describes what the linear relationship is between $$x$$ and $$y$$.

The relationship is described using an equation, which allows us to:

1. Predict values of $$y$$ from given values of $$x$$ (Sect. 35.4); and
2. Understand the relationship between $$x$$ and $$y$$ (Sect. 35.5).