Question:

Since 1975 the average fuel efficiency of U.S. cars and

Last updated: 7/26/2022

Since 1975 the average fuel efficiency of U.S. cars and

Since 1975 the average fuel efficiency of U.S. cars and light trucks (SUVs) has increased from 13.5 to 25.8 mpg, an increase of over 90%. A random sample of 73 cars from a large community got a mean mileage of 29.96 mpg per vehicle. The population standard deviation is 4 mpg. Estimate the upper bound true mean gas mileage with 95% confidence.