Use the following data set for Exercises 10–13.
| 18.7 | 2 | 100 | 4.1 |
| 18.4 | 4 | 90 | 5.0 |
| 21.8 | 6 | 90 | 3.8 |
| 22.0 | 8 | 70 | 5.2 |
| 25.2 | 10 | 70 | 3.8 |
| 25.7 | 12 | 50 | 5.3 |
| 26.9 | 14 | 50 | 5.4 |
| 28.3 | 16 | 30 | 5.4 |
| 28.6 | 18 | 30 | 4.3 |
| 31.8 | 20 | 10 | 4.9 |
12. Identify any predictors that have corresponding -values greater than the level of significance . Of these, discard the variable with the largest -value. Then redo Exercise 11, omitting this predictor. Repeat if necessary.