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 108 100 June 80 100 July 108 99 August 112 98 September 102 104 October 106 102 November 120 105 December 115 107 For the given forecast, the tracking signal = MADS (round your response to two decimal places)