Mathematics

Regression and Curve Fitting

It is often useful to find functions that describe the relationship between some variables you have observed. Identification of the coefficients of the function often leads to the formulation of an overdetermined system of simultaneous linear equations. You can find these coefficients efficiently by using the MATLAB backslash operator.

Suppose you measure a quantity y at several values of time t.

• t = [0 .3 .8 1.1 1.6 2.3]';
  y = [0.5 0.82 1.14 1.25 1.35 1.40]';
  plot(t,y,'o'), grid on
  
  
  

The following sections look at three ways of modeling the data:

• Polynomial regression
• Linear-in-the-parameters regression
• Multiple regression

Removing Outliers

Polynomial Regression