Your work at a company that sells 'Green' cars. You are interested in what proportion of your cars have mpg of 100 or more. In a sample of 25 green cars, 7 of them have mpg of 100 or more. Calculate a 95% confidence interval for the proportion of cars that have mpg of 100 or more. 1. Calculate p-tilde, the initial estimate for the proportion of cars with mpg of 100 or more.