Edsel Muffler, Inc., showed the following sales figures for its stainless steel muffler, Rusty, over the past five months:
Month Sales
August 220
September 240
October 180
November 200
December 160
Assume the base value at the end of November was 215 units and the trend value was -25.
a) What would be the forecast for the following February made at the end of December (α=0.2, β=0.4)
b) In case that no base value or trend was provided to you, what would be the forecast for the following February made at the end of December (α=0.2, β=0.4).