Discussion:
Q: A trucking firm suspects that the mean lifetime of a certain tire it uses is less than 35000 miles. To check the claim the firm randomly selects and test 54 of these tires and gets a mean lifetime of 34,570 with a standard deviation of 1200 miles. At a=0.05, test the trucking firms claim. Show all of your work, including the curve, write conclusion in language a layman can understand