Download Data Mining Association rule (Nathanael Chow)

CS 157B, Spring Semester 2007
By
Nathanael Chow
Overview
 What is data mining
 Association Rule
 Support
 Confidence
 Example
 Important of association rule
 References
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
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”
Association (cont.)
Association Rule
Association Rule Example
Customer
Items Purchased
1
Pizza, soda
2
Milk, pizza, window cleaner
3
Pizza, detergent
4
Pizza, detergent, soda
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
Pizza
4
1
1
2
2
Window
cleaner
1
1
1
0
0
Milk
1
1
1
0
0
Soda
2
0
0
2
1
Detergent
2
0
0
1
2
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
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
Association Rule Example (Cont.)
Associations
Support
Confidence
Pizza  Soda
50%
50%
Soda  Pizza
50%
100%
Pizza  detergent
50%
50%
Detergent  Pizza
50%
100%
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
References
 A. Silberschatz, H. Korth, S. Sudarshan, 2006.
Database System Concepts Fifth Edition
 http://cs.sjsu.edu/%7Elee/cs157b/cs157b.html
 http://www.cs.sjsu.edu/faculty/lee/cs157/cs157a.html