Engineers at the Manza car company have created a new engine that will hopefully create more gas efficiency. The engineers designed and tested 12 different engines. And found the following information...

Engineers at the Manza car company have created a new engine that will hopefully create more gas efficiency. The engineers designed and tested 12 different engines. And found the following information about gas efficiency: 34 mpg 37 mpg 41 mpg 36 mpg 38 mpg 40 mpg 39 mpg 38 mpg 36 mpg 42 mpg 39 mpg 37 mpg The engineers decided to determine the average mpg they wanted to use the 99% confidence interval. Find the interval.