The following are monthly actual and forecast demand levels for May thur December for un its of a products manufactured by the N. tamimi Pharmaceutical Company :
Month Actual demand Forecast Demansales
may 100 100
june 104 120
july 104 100
august 121 115
september 104 105
october 115 110
november 109 120
december 120 125
Compute a tracking signal and determine whether the forecasts are in control.(show work)