For 10 tanks of gas for your car, calculate the miles per gallon. (a) Construct a 95 percent confidence interval for the true mean mpg for your car. (b) How many tanks of gas would you need to obtain...

For 10 tanks of gas for your car, calculate the miles per gallon. (a) Construct a 95 percent confidence interval for the true mean mpg for your car. (b) How many tanks of gas would you need to obtain an error of ± 0.2 mpg with 95 percent confidence?