Your parents bought you a used car for your seventeenth birthday and you want to know how many miles to a gallon the car gets. You kept records for the miles you drove each time you filled up the tank with gas. For the first forty tanks of gas, you had a mean of 29.5 miles per gallon, with a standard deviation of 4.9. Using the table below, find the 90% confidence interval. Confidence Level (as a percent) -value 90 1.645 95 1.960 99 2.576 28.23 to 30.77 27.981 to 31.02 27.50 to 31.50 28.43 to 30.97