Basic Analysis and Graphing - SAS

Chapter 9 Bootstrapping 249
Example of Bootstrapping
Example of Bootstrapping
A tire manufacturer wants to predict an engine’s horsepower from the engine’s displacement (in 3 ). The
company is most interested in estimating the slope of the relationship between the variables. The slope
values help the company predict the corresponding change in horsepower when the displacement changes.
1. Open the Car Physical Data.jmp sample data table.
2. Select Analyze > Fit Y by X.
3. Assign Horsepower to the Y, Response role.
4. Assign Displacement to the X, Factor role.
5. Click OK.
6. Select Fit Line from the Bivariate Fit red triangle menu.
7. In the Parameter Estimates report, right-click the Estimate column and select Bootstrap
(Figure 9.2).
Figure 9.2 Select the Bootstrap Option
The column that you right-click is relevant when the Split Selected Column option is selected. For
more information, see “Bootstrap Window Options” on page 251.
8. Type 1000 for the Number of Bootstrap Samples.
9. Select Fractional Weights. Leave the Split Selected Column option selected.
10. Click OK.
The bootstrap process runs and produces two tables.
Next, analyze the bootstrapped slope.
11. Click on the table with the unstacked results for the slope and intercept, the table with 1,001 rows.
Figure 9.3 shows part of the table.