The following are monthly actual and forecast demand levels for May through December for units of a product manufactured by the D. Bishop Company in Des Moines: Month Actual Demand Forecast Demand May 105 102 June 78 104 July 108 101 August 112 104 September 108 104 October 110 104 November 125 105 December 125 109 What is the value of the tracking signal as of the end of december?

The value of the tracking signal as of the end of December is 8.

Explanation:

month actual forecast forecast RSFE absolute MAD Tracking signal

sales sales error error

May 105 102 3 3 3 3 1

june 78 104 - 26 - 23 - 26 - 11.5 2

july 108 101 7 - 16 7 - 5.33333 3

august 112 104 8 - 8 8 - 2 4

sep 108 104 4 - 4 4 - 0.8 5

oct 110 104 6 2 6 - 0.6667 - 3

nov 125 105 20 22 20 3.142857143 7

dec 125 109 16 38 16 4.75 8