Now that his car is 5 years old, he would like to know whether the variability of gas mileage has changed. He recorded the gas mileage from his last eight fill-ups; these are listed here. Conduct a test at a 10% significance level to infer whether the variability has changed.
The mean absolute deviation shows the average distance number data is from each other. The bigger it is the farther the numbers are away from each other and vice versa.
