2.5 Forecast current year quarterly motorcycle sales given data from the past 5 years shown in the following table. Suppose the actual quarterly sale during the current year is 140, 40, 35, and 80, what is the behavior of the tracking signal based on your model? What does this say about your model?

Quarter Year I

II III IV 1

40 12 8

20 2

60 15 15 30 3

80 20 20 40 4

100 20 30 50 5

120 30 30 60