Using Graphs for Information Extraction

Gasoline Consumption Example

Jan 12, 2010 STAT 100 1

Jan 12, 2010 STAT 100 2

Gasoline Consumption

Each Fill - record kms and litres of fuel used

Smooth--->SeasonalPattern

Jan 12, 2010 STAT 100 3

Theory of Smoothing

Smoothing amplifies signal but introduces bias

by cutting off peaks and valleys

Jan 12, 2010 STAT 100 4

Illustration of Effect – Artificial Data

Jan 12, 2010 STAT 100 5

Intro to smoothing with context …

Jan 12, 2010 STAT 100 6

Suggests follow-up

1. How do you choose the amount of smoothing to produce useful information?

2. Why does a seasonal pattern occur?