The following are monthly actual and forecast demand levels for May through December for units of a product manufactured by the Deborah Bishop Company in Des​ Moines:

Month
Actual Demand
Forecast Demand
May
100
102
June
80
108
July
108
101
August
112
104
September
102
100
October
114
104
November
130
105
December
120
107

Part 2
For the given​ forecast, the tracking signal​ =

MADs ​(round your response to two decimal​ places).