Data collected by a price reporting agency from more than 90,000 gasoline and convenience stores throughout the U.S. showed that the average price for a gallon of unleaded gasoline was $3.28. The following data show the price per a sample of 20 gasoline and convenience stores located in San Francisco. 3.39 3.59 4.79 3.36 3.35 3.51 3.85 3.80 3.95 3.36 3.57 3.59 3.75 4.19 4.15 3.86 3.43 3.53 3.61 3.57 (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. (Round your answer to the nearest cent.)