Polynomial Regression

Create new predictor variables by taking powers of our original predictor variables, $X^k\to$ kth order polynomial form

• if we have data of the form $(X,Y)$, we can make a new predictor variable $X_2=X^2$, a quadratic variable of the original $X_1=X$
• new form of the data as $(Y,X,X^2)=(Y,X_1,X_2)$