Toyota Inc. promises to sell a fuel economy vehicle with an interval of miles per gallon around the mean is within 31.2 to 49.2 miles. Suppose the average fuel economy for the 2013 Toyota Prius car is reported to be 39.2 miles per gallon with a standard deviation of 3.7 mpg.
A. Is company delivering Six Sigma quality to its customers?
B. If not, then how much should the standard deviation be reduced to get Six Sigma qualify?