A metropolitan transportation authority has set a bus mechanical reliability goal of 3,900 bus miles. Bus mechanical reliability is measured specifically as the number of bus miles between mechanical...

A metropolitan transportation authority has set a bus mechanical reliability goal of

bus miles. Bus mechanical reliability is measured specifically as the number of bus miles between mechanical road calls. Suppose a sample of

buses resulted in a sample mean of

bus miles and a sample standard deviation of

bus miles. Complete parts​ (a) and​ (b) below.

a. Is there evidence that the population mean bus miles is more than

bus​ miles? (Use a

level of​ significance.)