The EPA states that a 2013 Kia Optima should get 28 miles per gallon. The following data represent the miles per gallon of ten randomly selected 2013 Kia Optimas, as reported on FuelEconomy.gov. Is there significant ( = 0.05) evidence to conclude that a 2013 Kia Optima gets different gas mileage than the EPA states? A normal probability plot and boxplot indicate that the data are approximately normally distributed with no outliers.

30.2 19.9 30.3 23.3 19.4 20.2 26.7 16.7 17.6 27.5

In fact, the mean gas mileage is 28. What type of error was made, if any?