The manufacturer of a sports car claims that the fuel injectionsystem lasts 48 months before it needs to be replaced. A consumergroup tests this claim by surveying a random sample of 10 ownerswho had the fuel injection system replaced. The ages of the cars atthe time of replacement were (in months):
(i) Use your calculator to calculate the mean age of a car whenthe fuel injection system fails x and standard deviations. (Round your answers to two decimal places.)
(ii) Test the claim that the fuel injection system lasts less thanan average of 48 months before needing replacement. Use a 5% levelof significance.
What are we testing in this problem?
single proportionsingle meanĂ‚Â Ă‚Â Ă‚Â Ă‚Â
(a) What is the level of significance?
