Database Reference
In-Depth Information
Exercises
1. What is the Apriori property?
2. Following is a list of five transactions that include items A, B, C, and D:
• T1 :
{ A,B,C }
• T2 :
{ A,C }
• T3 :
{ B,C }
• T4 :
{ A,D }
• T5 :
{ A,C,D }
Which itemsets satisfy the minimum support of 0.5? (Hint: An itemset may
include more than one item.)
3. How are interesting rules identified? How are interesting rules
distinguished from coincidental rules?
4. A local retailer has a database that stores 10,000 transactions of last
summer. After analyzing the data, a data science team has identified the
following statistics:
•
{battery}
appears in 6,000 transactions.
•
{sunscreen}
appears in 5,000 transactions.
•
{sandals}
appears in 4,000 transactions.
•
{bowls}
appears in 2,000 transactions.
•
{battery,sunscreen}
appears in 1,500 transactions.
•
{battery,sandals}
appears in 1,000 transactions.
•
{battery,bowls}
appears in 250 transactions.
•
{battery,sunscreen,sandals}
appears in 600 transactions.
Answer the following questions:
a. What are the support values of the preceding itemsets?
b. Assuming the minimum support is 0.05, which itemsets are
considered frequent?
