AutoTrader.com would like to estimate the number of years owners keep the cars that they purchased as a new vehicle. The following data shows the age of seven vehicles that were sold for the first time by their owners.
9 3 5 1 8 5 3
Using this sample, the 90% confidence interval that estimates the average age of cars sold for the first time is
(3.24, 6.48)
(3.78, 5.94)
(4.32, 5.40)
(2.76, 6.96)