***I need help solving the questions d, e, f & g***

1. Observations of the demand for a certain part stocked at a parts supply depot during the calendar year 2013 were:
   1. Determine the one-step-ahead forecasts for the demand for January 2014 using 3, 4, and 6-month moving averages.

Month	Demand
January	99
February	107
March	144
April	221
May	177
June	280
July	223
August	286
September	212
October	275
November	188
December	312

1. Determine the one-step-ahead forecasts for the demand for January 2014 using 3, 4, and 6-month moving averages.

Formula:

Moving Average:

Moving Average = (A1 + A2 + ... + An) / n

Using 3-Month Moving Average:

Here n = 3

January 2014 Forecast = (312 + 188 + 275) / 3

January 2014 Forecast = 258.333333333

January 2014 Forecast = 258.33

Using 4-Month Moving Average:

Here n = 4

January 2014 Forecast = (312 + 188 + 275 + 212) / 4

January 2014 Forecast = 246.75

Using 6-Month Moving Average:

Here n = 6

January 2014 Forecast = (312 + 188 + 275 + 212 + 286 + 223) / 6

January 2014 Forecast = 249.333333333

January 2014 Forecast = 249.33

2. Using a three-moving average, determine the one-step-ahead forecasts for April through December 2013.

Here n = 3

Therefore:

April 2013 Forecast = (144 + 107 + 99) / 3 = 116.667

May 2013 Forecast = (221 + 144 + 107) / 3 = 157.333

June 2013 Forecast = (177 + 221 + 144) / 3 = 180.667

July 2013 Forecast = (280 + 177 + 221) / 3 = 226

August 2013 Forecast = (223 + 280 + 177) / 3 = 226.667

September 2013 Forecast = (286 + 223 + 280) / 3 = 263

October 2013 Forecast = (212 + 286 + 223) / 3 = 240.333

November 2013 Forecast = (275 + 212 + 286) / 3 = 257.667

December 2013 Forecast = (188 + 275 + 212) / 3 = 225

3. Using a four-month moving average, determine the one-step-ahead forecast for May through December 2013.

Here n = 4

Therefore:

May 2013 Forecast = (221 + 144 + 107 + 99) / 4 = 142.75

June 2013 Forecast = (177 + 221 + 144 + 107) / 4 = 162.25

July 2013 Forecast = (280 + 177 + 221 + 144) / 4 = 205.5

August 2013 Forecast = (223 + 280 + 177 + 221) / 4 = 225.25

September 2013 Forecast = (286 + 223 + 280 + 177) / 4 = 241.5

October 2013 Forecast = (212 + 286 + 223 + 280) / 4 = 250.25

November 2013 Forecast = (275 + 212 + 286 + 223) / 4 = 249

December 2013 Forecast = (188 + 275 + 212 + 286) / 4 = 240.25

4. Compute the MAD for the forecasts obtained in part (b) and (c). Which method gave better results? Based on forecasting theory, which method should have given better results?
5. What would an MA(1) forecasting method mean? Compare the accuracy of MA(1) and MA(4) forecasts for April through December 2013.
6. Determine the one-step-ahead exponential smoothing forecasts for August through December, assuming a=0.20 and the initial forecast the average of the first two periods.
7. Compare the accuracy of the forecasts obtained in part (f) with the one in part(c). Comment the reason of the result.