Forecasting: Time series and trend analysis
Classroom Example. Forecast for period # 8 using the five methods as shown in the tables below.
Find MAD and MAPE for each method. Which method is giving you the best forecast? Why?
|
|
|
Three period Simple |
Exponential Smoothing |
Naïve |
Method |
|
||||
|
|
|
Moving Average |
|
Method Alpha = 0.3 |
Forecast=Average Sales |
|||||
|
|
Sales |
Forecast Error |
%Error |
Forecast Error |
%Error |
Forecast Error |
%Error |
|||
|
Period |
Y |
Y cap |
Y –Y cap |
APE |
Y cap |
Y –Y cap |
APE |
Y cap |
Y –Y cap |
APE |
|
1 |
10 |
|
|
|
----- |
|
|
13 |
-3.00 |
30.00 |
|
2 |
14 |
|
|
|
10 |
4 |
28.571% |
13 |
1.00 |
7.14 |
|
3 |
12 |
|
|
|
|
.8 |
6.667% |
13 |
-1.00 |
8.33 |
|
4 |
11 |
12 |
-1 |
9.091% |
|
-.44 |
4% |
13 |
-2.00 |
18.18 |
|
5 |
15 |
12.333 |
2.667 |
17.778% |
|
3.692 |
24.613% |
13 |
2.00 |
13.33 |
|
6 |
13 |
12.667 |
.333 |
2.564% |
|
.584 |
4.495% |
13 |
0.00 |
0.00 |
|
7 |
16 |
13 |
3 |
18.75% |
|
3.409 |
21.307% |
13 |
3.00 |
18.75 |
|
Results |
=== |
14.667 |
1.75 |
12.046 |
13.61 |
2.154 |
14.942 |
13 |
1.71 |
13.68 |
|
|
|
Forecast |
MAD |
MAPE |
Forecast |
MAD |
MAPE |
Forecast |
MAD |
MAPE |
|
|
|
Trend Analysis |
Naïve |
Method |
|
||
|
|
|
|
|
Forecast=Last pd Actual |
|||
|
|
Sales |
Forecast Error |
%Error |
Forecast Error |
%Error |
||
|
Period |
Y |
Y cap |
Y –Y cap |
APE |
Y cap |
Y –Y cap |
APE |
|
1 |
10 |
10.964 |
-.964 |
9.643% |
|
|
|
|
2 |
14 |
11.643 |
2.357 |
16.837% |
10 |
4 |
28.571% |
|
3 |
12 |
12.321 |
-.321 |
2.679% |
14 |
-2 |
16.667% |
|
4 |
11 |
13 |
-2 |
18.182% |
12 |
-1 |
9.091% |
|
5 |
15 |
13.679 |
1.321 |
8.81% |
11 |
4 |
26.667% |
|
6 |
13 |
14.357 |
-1.357 |
10.44% |
15 |
-2 |
15.385% |
|
7 |
16 |
15.036 |
.964 |
6.027% |
13 |
3 |
18.75% |
|
Results |
=== |
15.714 |
1.327 |
10.374 |
16 |
2.667 |
19.188% |
|
|
|
Forecast |
MAD |
MAPE |
Forecast |
MAD |
19.188% |