A SRS of 20 new car models yielded the data shown to the right on fuel tank capacity, in gallons. a) Determine a 95% confidence interval for the mean fuel tank capacity of all new car models. Assume = 3.40 gallons. b) How would you decide whether fuel tank capacities for new car models are approximately normally distributed? c) Must fuel tank capacities for new car models be exactly normally distributed for the confidence interval that you obtained in part (a) to be approximately correct? Explain your answer.

table of data

15.1 16.5 22.9 16.7 18.9

21.6 20.7 16.2 18.8 20.2

15.9 21.8 16.6 22.9 22.7

20.8 16.2 21.6 17.6 21.8