Calculate the sales of gasoline to be expected in each quarter of the year. b) Suppose another research proposes to use the same data to estimate an equation of the same form, except that she wishes to employ dummy variables 2 S , 3 S , and 4 S . Write down the equation that will come from her calculations. c) Yet another investigator proposes to suppress the intercept and use all four seasonal dummies. Write down the results of his estimation.