16.43 The Platinum Gasaver.
Platinum Gasaver is a device its maker says “may increase gas mileage by 22%.” An advertisement reports the results of a matched pairs study with 15 identical vehicles. The claimed percent changes in gas mileage with the Gasaver are
gasaver
| 48.3 | 46.9 | 46.8 | 44.6 | 40.2 | 38.5 | 34.6 | 33.7 |
| 28.7 | 28.7 | 24.8 | 10.8 | 10.4 | 6.9 | −12.4 |
Is there good evidence that the Gasaver improves median gas mileage by 22% or more? (Apply the Wilcoxon signed rank test to the differences between the sample percents and the claimed 22%.)
16.43
From software: , . The data do not show a systematic difference between the sample percents and the claimed 22%.