Data collected by the Oil Price Information Service from more than gasoline and convenience stores throughout the U. S. showed that the average price for a gallon of unleaded gasoline was (MSN Auto website). The following data show the price per gallon () for a sample of gasoline and convenience stores located in San Francisco. 3.59 3.57 3.59 3.59 4.79 3.55 3.56 3.99 3.55
4.15 3.71 3.66 3.65 3.63 3.60 3.73 3.75 3.61

Required:
a. Use the sample data to estimate the mean price for a gallon of unleaded gasoline in San Francisco.
b. Compute the sample standard deviation.
c. Compare the mean price per gallon for the sample data to the national average price. What conclusions can you draw about the cost living in San Francisco?