Question 2 (Time-series forecasting) 1. (3 points) Dummy variables corresponding to first, second, and third quarters were added to the linear trend model. These indicator variables are X1, X2, and X3 (the excluded category is quarter 4). The estimated trend-and-season model is Supply 100+ 20t-15X120X2 - 10X3 where t is the number of periods (quarters) elapsed since the beginning of the series. Based on this regression equation, draw (by hand or attaching a plot from software) the time-series plot for expected sales, starting at t= 0 and ending at t = 10 (note: the relationship should be a time-series of dots connected by lines). Assume that at t = 0, we are in quarter 1. Draw your time-series plot here: