Polynomial Regression

Polynomial regression is a model that describes the relationship between x and y as an n^th degree polynomial.

$f(x)=\omega _{0}+\omega _{1}x+\omega _{2}x^{2}+...+\epsilon$

Notice that polynomial regression is a form of Linear Regression, except there are higher-degree attributes.

To build a polynomial model involves determining the degree of polynomial and using normal linear regression methods.

Degree

A higher degree means a more complex model. While it increases the accuracy of the model, higher degree models more computationally expensive and an overly high degree will result in overfitting. RMS error can be used to determine what degree is sufficient; After a certain degree of polynomial, the RMS error on the test data would increase.