CK-12-Calculus

1.3. Models and Data http://www.ck12.org

Since our calculator will also allow for a variety of non-linear functions to be used as models, we can therefore
examine quite a few real life situations. We will first consider an example of quadratic modeling.
Quadratic Models
Example 2:
The following table lists the number of Food Stamp recipients (in millions) for each year after 1990.

TABLE1.2:

years after 1990 Participants

1 22. 6

2 25. 4

3 27. 0

4 27. 5

5 26. 6

6 25. 5

7 22. 5

8 19. 8

9 18. 2

10 17. 2

We enter the data in our calculator inL3andL4(that enables us to save the last example’s data). We then will view
a scatter plot. Change the window ranges accordingly to include all of the data. Use[− 2 , 10 ]forxand[− 2 , 30 ]fory.
Here is the scatter plot:

Now let us compute the regression equation. Since our scatter plot suggests a quadratic model for the data, we will
chooseQuadratic Regressionfrom the menu. We get the equation:

y=− 0. 30 x^2 + 2. 38 x+ 21. 67.