Reconsider Prob. 27.7-4. For each of the forecasting methods specified in parts (b), (c), and (d), use the corresponding procedure in the forecasting area of your IOR Tutorial to obtain the requested forecasts. Then use the accompanying graph that plots both the sales data and forecasts to answer the following questions for these forecasting methods.
(a) Based on your examination of the graphs for the three forecasting methods, which method do you feel is doing the best job of forecasting with the given data? Why?
(b) Ben Swanson now has found that an error was made in determining the sales for April, but he has not yet obtained the corrected sales figure. For each of the three forecasting methods, Ben wants to know which of the original monthly forecasts would change now because of changing the sales figure for April. Answer this question by dragging vertically the blue dot that corresponds to April sales and observing which of the red dots (corresponding to monthly forecasts) move.
(c) Repeat part (b) if the sales for April change from 28 to 16.
(d) Repeat part (b) if the sales for April change from 28 to 40.