We've talked about linear regression where we fit a straight line to a set of observations. Polynomial regression is our next topic, and that's using higher order polynomials to fit your data. So, sometimes your data might not really be appropriate for a straight line. That's where polynomial regression comes in.
Polynomial regression is a more general case of regression. So why limit yourself to a straight line? Maybe your data doesn't actually have a linear relationship, or maybe there's some sort of a curve to it, right? That happens pretty frequently.
Not all relationships are linear, but the linear regression is just one example of a whole class of regressions that we can do. If you remember the linear regression line that we ended up with was of the form y = mx + b, where we got back the values m and b from our linear regression...