According to a leasing firm's reports, the mean number of miles driven annually in its leased cars is 13,420 miles with a standard deviation of 3340miles. The company recently starting using new contracts which require customers to have the cars serviced at their own expense. The company's owner believes the mean number of miles driven annually under the new contracts,, is less than 13,420 miles. He takes a random sample of 28 cars under the new contracts. The cars in the sample had a mean of 11,893 annual miles driven. Assume that the population is normally distributed. Is there support for the claim, at the 0.05 level of significance, that the population mean number of miles driven annually by cars under the new contracts, is less than 13,420 miles? Assume that the population standard deviation of miles driven annually was not affected by the change to the contracts.

Perform a one-tailed test. Then complete the parts below.

Carry your intermediate computations to three or more decimal places, and round your responses as specified below.

(a)	State the null hypothesis H0 and the alternative hypothesis H1 .
H0:
H1:
(b)	Determine the type of test statistic to use.
	(Choose one)
(c)	Find the value of the test statistic. (Round to three or more decimal places.)
(d)	Find the critical value. (Round to three or more decimal places.)
(e)	Can we support the claim that the population mean number of miles driven annually by cars under the new contracts is less than 13,420 miles?
Yes No