For a quality control test, a company checks the miles per gallon (mpg) for a simple random sample of n=100 minivans drawn from its current inventory. The average mpg of these 100 minivans is 15.6 with a standard deviation of 1.9 mpg. We want a confidence interval for the average mpg of all minivans in the company's inventory. Required:
Set up an approximate 95% confidence interval for the average mpg of all minivans in the company's inventory.