Least squares offers the most generic form of fitting for supervised learning.

We will focus on **linear least squares** to start out.

It provides a conceptually simple method for investigating a functional relationship between one or more

**factors**and an**outcome**of interest.The relationship is expressed in the form of an equation, our

**model**, connecting the**response**or**dependent variable**to one or more**explanatory variables**.

We will start with just **two** variables.

- Don't worry, we will get fancy in due course.