The file Natural Gas contains the U.S. monthly average commercial and residential price for natural gas in dollars per thousand cubic feet from January 2008 through December 2016. Source: Data extracted from “U.S. Natural Gas Prices,” bit.ly/2oZIQ5Z, accessed March 19, 2017. For the commercial price and the residential price: a. Construct a time-series plot. b. What pattern, if any, is present in the data? c. Construct a scatter plot of the commercial price and the residential price. d. What conclusion can you reach about the relationship between the commercial price and the residential price?
