In: Statistics and Probability
Please run Moving Average with 2 and 3 periods; Exponential Smoothing with a smoothing factor, or alpha, of 0.1 , 0.5 and 0.9; and Classical Decomposition for the data listed below.
Which model is best? Please explain how you were able to run each model using Microsoft Excel.
| Year | Quarter | Sales | Advertising |
| 1 | 1 | 144 | 41 |
| 2 | 151 | 51 | |
| 3 | 134 | 32 | |
| 4 | 151 | 45 | |
| 2 | 1 | 145 | 48 |
| 2 | 145 | 34 | |
| 3 | 141 | 29 | |
| 4 | 166 | 43 | |
| 3 | 1 | 151 | 40 |
| 2 | 164 | 51 | |
| 3 | 151 | 39 | |
| 4 | 176 | 54 | |
| 4 | 1 | 170 | 41 |
| 2 | 180 | 52 | |
| 3 | 156 | 48 | |
| 4 | 187 | 47 | |
| 5 | 1 | 166 | 44 |
| 2 | 182 | 48 | |
| 3 | 154 | 44 | |
| 4 | 169 |
36 |
The 2 period Moving Average (MA) forecast for sales
The data values are,
| Period | Sales |
| 1 | 144 |
| 2 | 151 |
| 3 | 134 |
| 4 | 151 |
| 5 | 145 |
| 6 | 145 |
| 7 | 141 |
| 8 | 166 |
| 9 | 151 |
| 10 | 164 |
| 11 | 151 |
| 12 | 176 |
| 13 | 170 |
| 14 | 180 |
| 15 | 156 |
| 16 | 187 |
| 17 | 166 |
| 18 | 182 |
| 19 | 154 |
| 20 | 169 |
The average of two period is obtained by taking the average of the current year and the previous three year.
| Period | Sales | MA period =2 |
| 1 | 144 | ### |
| 2 | 151 | =(144+151)/2=147.5 |
| 3 | 134 | =(151+134)/2=142.5 |
| 4 | 151 | =(134+151)/2=142.5 |
| 5 | 145 | =(1151+145)/2=148 |
| 6 | 145 | =(145+145)/2=145 |
| 7 | 141 | =(145+141)/2=143 |
| 8 | 166 | =(141+166)/2=153.5 |
| 9 | 151 | =(166+151)/2=158.5 |
| 10 | 164 | =(151+164)/2=157.5 |
| 11 | 151 | =(164+151)/2=157.5 |
| 12 | 176 | =(151+176)/2=163.5 |
| 13 | 170 | =(176+170)/2=173 |
| 14 | 180 | =(170+180)/2=175 |
| 15 | 156 | =(156+180)/2=168 |
| 16 | 187 | =(156+187)/2=171.5 |
| 17 | 166 | =(187+166)/2=176.5 |
| 18 | 182 | =(166+182)/2=174 |
| 19 | 154 | =(154+182)/2=168 |
| 20 | 169 | =(154+169)/2=161.5 |
In forecast one of the way to measure error is mean square error (MSE). The means square error is the average of the squared differences between the forecast and observed values.
| Period | Sales | MA period =2 | Difference | Difference^2 |
| 1 | 144 | ### | ||
| 2 | 151 | 147.5 | 3.5 | 12.25 |
| 3 | 134 | 142.5 | -8.5 | 72.25 |
| 4 | 151 | 142.5 | 8.5 | 72.25 |
| 5 | 145 | 148 | -3 | 9 |
| 6 | 145 | 145 | 0 | 0 |
| 7 | 141 | 143 | -2 | 4 |
| 8 | 166 | 153.5 | 12.5 | 156.25 |
| 9 | 151 | 158.5 | -7.5 | 56.25 |
| 10 | 164 | 157.5 | 6.5 | 42.25 |
| 11 | 151 | 157.5 | -6.5 | 42.25 |
| 12 | 176 | 163.5 | 12.5 | 156.25 |
| 13 | 170 | 173 | -3 | 9 |
| 14 | 180 | 175 | 5 | 25 |
| 15 | 156 | 168 | -12 | 144 |
| 16 | 187 | 171.5 | 15.5 | 240.25 |
| 17 | 166 | 176.5 | -10.5 | 110.25 |
| 18 | 182 | 174 | 8 | 64 |
| 19 | 154 | 168 | -14 | 196 |
| 20 | 169 | 161.5 | 7.5 | 56.25 |
| MSE = | 1467.75 |

Similarly,
The 3 period Moving Average (MA) forecast is obtained below,
| Period | Sales | MA period =2 | Difference | Difference^2 |
| 1 | 144 | ### | ||
| 2 | 151 | ### | ### | |
| 3 | 134 | 143 | -9 | 81 |
| 4 | 151 | 145.3333333 | 5.666666667 | 32.11111111 |
| 5 | 145 | 143.3333333 | 1.666666667 | 2.777777778 |
| 6 | 145 | 147 | -2 | 4 |
| 7 | 141 | 143.6666667 | -2.666666667 | 7.111111111 |
| 8 | 166 | 150.6666667 | 15.33333333 | 235.1111111 |
| 9 | 151 | 152.6666667 | -1.666666667 | 2.777777778 |
| 10 | 164 | 160.3333333 | 3.666666667 | 13.44444444 |
| 11 | 151 | 155.3333333 | -4.333333333 | 18.77777778 |
| 12 | 176 | 163.6666667 | 12.33333333 | 152.1111111 |
| 13 | 170 | 165.6666667 | 4.333333333 | 18.77777778 |
| 14 | 180 | 175.3333333 | 4.666666667 | 21.77777778 |
| 15 | 156 | 168.6666667 | -12.66666667 | 160.4444444 |
| 16 | 187 | 174.3333333 | 12.66666667 | 160.4444444 |
| 17 | 166 | 169.6666667 | -3.666666667 | 13.44444444 |
| 18 | 182 | 178.3333333 | 3.666666667 | 13.44444444 |
| 19 | 154 | 167.3333333 | -13.33333333 | 177.7777778 |
| 20 | 169 | 168.3333333 | 0.666666667 | 0.444444444 |
| MSE = | 1115.777778 |

The Exponential smoothing forecast method,
For smoothing factor
Forecast for second month is,




| Period | Sales | Exponential Smoothing, alpha = 0.1 | Difference | Difference^2 |
| 1 | 144 | |||
| 2 | 151 | 144 | 7 | 49 |
| 3 | 134 | 144.7 | -10.7 | 114.49 |
| 4 | 151 | 143.63 | 7.37 | 54.3169 |
| 5 | 145 | 144.367 | 0.633 | 0.400689 |
| 6 | 145 | 144.4303 | 0.5697 | 0.32455809 |
| 7 | 141 | 144.48727 | -3.48727 | 12.16105205 |
| 8 | 166 | 144.138543 | 21.861457 | 477.9233022 |
| 9 | 151 | 146.3246887 | 4.6753113 | 21.85853575 |
| 10 | 164 | 146.7922198 | 17.20778017 | 296.1076984 |
| 11 | 151 | 148.5129978 | 2.487002153 | 6.185179709 |
| 12 | 176 | 148.7616981 | 27.23830194 | 741.9250924 |
| 13 | 170 | 151.4855283 | 18.51447174 | 342.785664 |
| 14 | 180 | 153.3369754 | 26.66302457 | 710.9168792 |
| 15 | 156 | 156.0032779 | -0.003277887 | 1.07445E-05 |
| 16 | 187 | 156.0029501 | 30.9970499 | 960.8171026 |
| 17 | 166 | 159.1026551 | 6.897344911 | 47.57336682 |
| 18 | 182 | 159.7923896 | 22.20761042 | 493.1779606 |
| 19 | 154 | 162.0131506 | -8.013150622 | 64.21058289 |
| 20 | 169 | 161.2118356 | 7.78816444 | 60.65550535 |
| MSE = | 4454.83008 |

For smoothing factor
Forecast for second month is,




| Period | Sales | Exponential Smoothing, alpha = 0.5 | Difference | Difference^2 |
| 1 | 144 | |||
| 2 | 151 | 144 | 7 | 49 |
| 3 | 134 | 147.5 | -13.5 | 182.25 |
| 4 | 151 | 140.75 | 10.25 | 105.0625 |
| 5 | 145 | 145.875 | -0.875 | 0.765625 |
| 6 | 145 | 145.4375 | -0.4375 | 0.19140625 |
| 7 | 141 | 145.21875 | -4.21875 | 17.79785156 |
| 8 | 166 | 143.109375 | 22.890625 | 523.9807129 |
| 9 | 151 | 154.5546875 | -3.5546875 | 12.63580322 |
| 10 | 164 | 152.7773438 | 11.22265625 | 125.9480133 |
| 11 | 151 | 158.3886719 | -7.388671875 | 54.59247208 |
| 12 | 176 | 154.6943359 | 21.30566406 | 453.9313211 |
| 13 | 170 | 165.347168 | 4.652832031 | 21.64884591 |
| 14 | 180 | 167.673584 | 12.32641602 | 151.9405318 |
| 15 | 156 | 173.836792 | -17.83679199 | 318.1511486 |
| 16 | 187 | 164.918396 | 22.081604 | 487.5972354 |
| 17 | 166 | 175.959198 | -9.959197998 | 99.18562476 |
| 18 | 182 | 170.979599 | 11.020401 | 121.4492382 |
| 19 | 154 | 176.4897995 | -22.4897995 | 505.7910815 |
| 20 | 169 | 165.2448997 | 3.75510025 | 14.10077789 |
| MSE = | 3246.02019 |
For smoothing factor
Forecast for second month is,




| Sales | Exponential Smoothing, alpha = 0.5 | Difference | Difference^2 |
| 144 | |||
| 151 | 144 | 7 | 49 |
| 134 | 150.3 | -16.3 | 265.69 |
| 151 | 135.63 | 15.37 | 236.2369 |
| 145 | 149.463 | -4.463 | 19.918369 |
| 145 | 145.4463 | -0.4463 | 0.19918369 |
| 141 | 145.04463 | -4.04463 | 16.35903184 |
| 166 | 141.404463 | 24.595537 | 604.9404403 |
| 151 | 163.5404463 | -12.5404463 | 157.2627934 |
| 164 | 152.2540446 | 11.74595537 | 137.9674676 |
| 151 | 162.8254045 | -11.82540446 | 139.8401907 |
| 176 | 152.1825404 | 23.81745955 | 567.2713796 |
| 170 | 173.618254 | -3.618254045 | 13.09176233 |
| 180 | 170.3618254 | 9.638174596 | 92.89440953 |
| 156 | 179.0361825 | -23.03618254 | 530.665706 |
| 187 | 158.3036183 | 28.69638175 | 823.4823253 |
| 166 | 184.1303618 | -18.13036183 | 328.7100199 |
| 182 | 167.8130362 | 14.18696382 | 201.2699424 |
| 154 | 180.5813036 | -26.58130362 | 706.565702 |
| 169 | 156.6581304 | 12.34186964 | 152.3217462 |
| MSE = | 5043.68737 |
From each forecast method applied above foe sales forcast,

Hence, the moving average forcast method for period = 3 is best fit for the sales data.
Similarly the forecast method can be applied to advertising data.
I am working on rest of the part. I'll upload it soon