In a transportation study of 27 large cities it was found that the number of motor vehicles per household was normally distributed with a mean of 1.34. The study also stated that the sample deviation, s, was 0.46. Find a 90% confidence interval for the true mean number of cars per household. Please show your work and if you use a calculator shortcut for anything please state what you entered as I'm really trying to learn how to use a calculator. Thank you