Quadratic Regression
A quadratic regression is the process of finding the equation of the parabola that fits best for a set of data. As a result, we get an equation of the form
where 
.
The relative predictive power of a quadratic model is denoted by R 2 . The value of R 2 varies between 0 and 1. The more close the value is to 1, the more accurate the model is.
Example 1:
Consider the set of data. Determine the quadratic regression for the set.
(–3, 7.5), (–2, 3), (–1, 0.5), (0, 1), (1, 3), (2, 6), (3, 14)
Enter the x -coordinates and y -coordinates in your calculator and do a quadratic regression. The equation of the parabola that best approximates the points is
Plot the graph. You should get a graph like this.
You can see that the R 2 value for the data is 0.9942.
