An auto parts company is interested in how long people plan to own their cars. They collect the following data by asking 18 car owners how many years they will drive their current car from the time they bought it until they trade it in:
5 7 8 4 9 10 8 5 4 1 1 2 4 3 5 4 2 7
Make a 95% confidence interval for the length of time these car owners will keep their cars.
find the std.
How many std define a 95% interval?
review the Z table.