Various State and National Automobile Associations Regularly Survey Gasoline Stations $\mu , \sigma , \bar { x } , s$

Various state and national automobile associations regularly survey gasoline stations to determine the current retail price of gasoline. Suppose one such national association contacts 200 stations in the United States to determine the price of regular unleaded gasoline at each station. In the context of this problem, define the following descriptive measures: $\mu , \sigma , \bar { x } , s$