In 2008, a small dealership leased 21 Suburu Outbacks on 2-year leases. When the cars were returned in 2010, the mileage was recorded (see below). Is the dealer’s mean significantly greater than the...

In 2008, a small dealership leased 21 Suburu Outbacks on 2-year leases. When the cars were returned in 2010, the mileage was recorded (see below). Is the dealer’s mean significantly greater than the national average of 30,000 miles for 2-year leased vehicles, using the 10 percent level of significance?