(Winter's Method) A popular brand of tennis shoes has had the following demand history by quarters over a three-year period. Table 2: Data for Problem 3 (a) Using the data from Years 2 and 3, determine initials values of the intercept, slope, and seasonal factors for Winter's method. (b) Assume the observed demand for the first quarter of Year 4 was 18. Using =0.2, =0.15,=0.1, update the estimates of the series, the slope and the seasonal actors. (c) What are the forecasts made at the end of the first quarter of Year 4 for the remaining three quarters of Year 4 ? (d) Suppose the observed quarterly demand for Year 4 was 18, 51, 86, 66. Determine updated estimates of the slope, the intercept, and the seasonal factors for the end of Year 4. Using these updated estimates, determine the forecasts that Winter's method gives for all of Year 6 made at the end of Year 4. Use the values of the smoothing constants given in part (b)