Table: contains six-month average price data for styrene and its feedstock's ethylene and benzene for South Korea over the period Jan. 1999 to Dec. 2010. Calculate the gross margin
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For making styrene from benzene and ethylene and plot how the gross margin varied over this time period. Develop a forecast of the gross margin of styrene from benzene and ethylene for the time period 2010 to 2030.