The Washington Metropolitan Area Transit Authority has set a bus fleet reliability goal of 8,000 bus miles. Bus reliability is measured specifically as the number of bus miles traveled before a mechanical breakdown that requires the bus to be removed from service or deviate from the schedule. Suppose a sample of 64 buses resulted in a sample mean of 8,210 bus miles and a sample standard deviation of 625 bus miles.

a. Is there evidence that the population mean bus miles is greater than 8,000 bus miles? (Use a 0.05 level of significance.)

b. Determine the p-value and interpret its meaning.