In: Statistics and Probability
The manufacturer of a sports car claims that the fuel injection system lasts 48 months before it needs to be replaced. A consumer group tests this claim by surveying a random sample of 10 owners who had the fuel injection system replaced. The ages of the cars at the time of replacement were (in months):
27 | 46 | 47 | 48 | 53 | 46 | 30 | 51 | 42 | 52 |
(i) Use your calculator to calculate the mean age of a car when the fuel injection system fails x and standard deviation s. (Round your answers to two decimal places.)
x = | months |
s = | months |
(ii) Test the claim that the fuel injection system lasts less than
an average of 48 months before needing replacement. Use a 5% level
of significance.
What are we testing in this problem?
single proportionsingle mean
(a) What is the level of significance?