Ten sixth-grade students in five different countries—United States, Australia, South Africa, Canada, and New Zealand—were asked about their travel times to school. Their responses were organized into five data sets. The mean and MAD of each data set are shown in the table.
1. Which group of students has the greatest variability in their travel times?
2. The mean of the data set for New Zealand is close to that of Canada. What does this tell us about the travel times of students in those two data sets?
3. The MAD of the data set for New Zealand is quite different than that of Canada. What does this tell us about the travel times of students in those two data sets?

Mean MAD
United States: 9 4.2
Australia: 18.1 7.9
South Africa: 23.5 16.2
Canada: 11 8
New Zealand: 12.3 5.5