A trucking firm suspects that the mean life of a certain tire it uses is less than 35,00 miles. To check the claim, the firm randomly selects and tests 18 of these tires and gets a mean lifetime of 34,450 miles with a standard deviation of 1200 miles. Ata = 0.05, test the trucking firm's claim.

(a) State the Null and Alternative Hypothesis for this test.

(b) Draw the critical region sketch using the 5% level of significance.

(c) Calculate the test statistic.

(d) Make a decision concerning the null hypothesis.

(e) What conclusion concerning the claim can be made?