question 2 10 marks: De monthly series. In particular, what dummy variable(s) would you use to capture the relevant effects: a) A sporting goods store finds that detrended monthly sales are about the same for each month in a given 3-month season. For example, sales are similar in the winter months of January, February, March; in the spring months of April, May, June, and so on. b) A campus bookstore finds that detrended sales are similar for all first, all second, all third and all fourth months of each semester. For example, sales are similar in Japuary May and September, the first months of the first, second and third trimesters, respectively