1. Data Mining-Association Rule
CS 157B, Spring Semester 2007 By
Nathanael Chow

2. Overview What is data mining Association Rule
Support
Confidence
Example
Important of association rule
References

3. What is Data Mining?
Data mining is the process of searching large volumes of data for patterns, correlations, and trends.
Database
Data
Mining
Patterns or
Knowledge
Decision
Support

4. Associations Frequently co-occurring features
Example: someone who buys bread is quiet likely also to buy milk
Amazon: customer who buys “Gladiator” will also buys “Brave Heart”

5. Association (cont.)

6. Association Rule

7. Association Rule Example
Customer
Items Purchased 1
Pizza, soda 2
Milk, pizza, window cleaner 3
Pizza, detergent 4
Pizza, detergent, soda

8. Association Rule Example (cont.)
Customer
Items Purchased 1
Pizza, soda 2
Milk, pizza, window cleaner 3
Pizza, detergent 4
Pizza, detergent, soda
Pizza
Window cleaner
Milk
Soda
Detergent 4 1 2

9. Association Rule Example (Cont.)
Pizza  Soda min_support >= 50%
min_conf >= 50%
Support: pizza U soda = 2/4 = 50%
Confidence: (pizza U soda) / (pizza) = 2/4
= 50%
Conclude: Pizza  Soda

10. Association Rule Example (Cont.)
Soda  Pizza min_support >= 50%
min_conf >= 50%
Support: soda U pizza = 2 / 4 = 50 %
Confidence: (soda U pizza) / (soda) = 2 / 2
= 100 %
Conclude: Soda  Pizza

11. Association Rule Example (Cont.)
Associations
Support
Confidence
Pizza  Soda
50%
Soda  Pizza
100%
Pizza  detergent
Detergent  Pizza

12. Important of knowing association rule
Supper market: to get a better profit(sale) by placing the associate items next to each other
Online sale: higher sales by placing real time advertising

14. References
A. Silberschatz, H. Korth, S. Sudarshan, Database System Concepts Fifth Edition