Computer sales over the past 4 months have been 35, 34, 38, and 44 units.
„L Using a 3-month moving average, forecast sales for the next month.
(35+34+38)/3 = 35.67
(34+ 38+44)3 = 38.67
„L Using a 3-month weighted moving average with the weights 3, 2, and 1, and with the most weight on the most recent data, forecast the next period¡¦s sales.
[(1x44) + (3x38) + (3x34)]/6=
1x44= 44
3x38=114
3x34=102
44+114+102=260/6 = 43.3
„L Calculate the forecast using exponential smoothing with an alpha of 1 and a first period¡¦s forecast of 35.
New forecast (NF) = 44
Last period¡¦s forecast (LPF) =38
Last period¡¦s actual demand = 38.67
(NF=LPF + a (LPAD ¡VLPF)
35 + 1 (44-35)
35 +1 (9)
35 + 9
44
I am kinder lost on this, not sure if I did it correctly.
Based on the information you provided, it seems like you have correctly calculated the forecasted sales using the moving average method and the weighted moving average method. For the 3-month moving average, you correctly calculated the average of the past 3 months' sales and got a forecast of 35.67 units. For the 3-month weighted moving average, you correctly applied the weights to each month's sales, calculated the sum, and divided by the total weight to get a forecast of 43.3 units.
However, there seems to be an error in your calculation for the exponential smoothing method. The formula you used: NF = LPF + a (LPAD - LPF), where NF is the new forecast, LPF is the last period's forecast, LPAD is the last period's actual demand, and a is the smoothing constant (alpha).
In your calculation, you used a smoothing constant (alpha) of 1, which means the forecast will completely ignore the historical data and only rely on the most recent forecast. This is not correct because a smoothing constant should typically be less than 1 to give appropriate weight to the historical data.
To calculate the forecast using exponential smoothing with an alpha of 1, you need to use the formula: NF = LPF + a (LPAD - LPF)
In this case, LPF is 35 and LPAD is not provided, but it should be the last period's actual sales, which is 38.67 units. So the calculation should be:
NF = 35 + 1 (38.67 - 35)
= 35 + 1 (3.67)
= 35 + 3.67
= 38.67
Therefore, the correct forecast using exponential smoothing with an alpha of 1 and a first period's forecast of 35 is 38.67 units.
I hope this clears up your confusion. Let me know if you have any further questions.