218. A-N-N

Simple exponential smoothing

Example:

Given

  • Smoothing parameter:
  • Initial level:
  • Data:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
12 10 8 11 14 12 9 13 16 14 11 15 18 16 13 17

Step 1 — formula

Observation:

Innovation (rearrange):

State update:

One-step-ahead forecast:

Step 2 — apply at

Use and :

Step 3 — iterate

Values rounded to 4 decimal places; arithmetic performed at full precision.

1 12
2 10
3 8
4 11
5 14
6 12
7 9
8 13
9 16
10 14
11 11
12 15
13 18
14 16
15 13
16 17

Forecast for any future : (flat — SES has no trend).