For Exercises 49–56, do the following:
56. Price of Milk. The U.S. Bureau of Labor Statistics reported that the mean price for a gallon of milk in 2011 was $3.34. A random sample of 100 retail establishments this year provides a mean price of $3.39. Assume . Perform a hypothesis test, using level of significance , to investigate whether the population mean price of milk this year has increased from the 2011 value.