# Linear Regression with One Predictor Variable

• $X$: the independent variable
• $Y$: the dependent variable

## 1.1 realtions between varaibles

### functional relation between two variables

Def: a functional relationship between two variables: $Y = f(X)$

Given a particular value of $X$, the function $f$ indicates the corresponding value of $Y$.

Example:

• $X$: the number of units sold
• $Y$: dollar sales