Polynomial Regression: New Columns, Same Least Squares

This dataset is of an experiment using the internal combusion engine (like what cars have). We are trying to predict a pollutant \(y=\) NOx (the concentration of nitrogen oxides in the exhaust) based on a measure of how rich or lean the fuel–air mixture is, \(x=\) E. Everything is centered, so the plots, the equation and the matrices share one coordinate system.