Due primarily to the price controls of the Organization of Petroleum Exporting Countries (OPEC), a cartel of crude-oil suppliers, the price of crude oil rose dramatically from the mid-1970s to the mid-1980s. As a result, motorists saw an upward spiral in gasoline prices. The data in the table below are typical prices for a gallon of regular leaded gasoline and a barrel of crude oil (refiner acquisition cost) for the years 1975-1996.

a. Use the STATISTIX printout on p. 486 to find the least squares line that describes the relationship between the price of a gallon of gasoline and the price of a barrel of crude oil over the 22-year period.

b. Construct a scattergram of all the data.
C. Plot your least squares line on the scattergram. Does your least squares line appear to be an appropriate characterization of the relationship between y and x over the 22-year period?

d. According to your model, if the price of crude oil fell to $15 per barrel, to what level (approximately)
would the price of regular leaded gasoline fall'? Justify your answer.