Many factors influence the retail price of gasoline. The following table shows the average retail price for a gallon of regular grade gasoline for each year from 2011 through 2014 (U.S. Energy Information Administration website, April 2015).
Year................ Average Price ($)
2011.............................. 3.521
2012.............................. 3.618
2013.............................. 3.505
2014.............................. 3.358
a. Use 2011 as the base year and develop a price index for the retail price of a gallon of regular grade gasoline over this four-year period.
b. Use 2012 as the base year and develop a price index for the retail price of a gallon of regular grade gasoline over this four-year period.