Association Analysis Flashcards
Association Rule Mining
Given a set of transactions, find rules that will predict the occurrence of an item based on the occurrences of other items in the transaction.
2 Rule Evaluation Metrics
Support - A measure of absolute frequency (Fraction that contain an itemset)
Confidence (c): A measure of correlative frequency.
3 Step of Brute-force approach
List all possible association rules
Compute the support and confidence for each rule
Prune rules that fail the minsup and minconf
Formula of
Total number of itemsets
Total number of possible association rules
Combination Formula
Total number of itemsets = 2k-1
Total number of possible association rules: 3k - 2k+1 + 1
Combination Formula: C(n,r) = nCr = n! / ((n - r )! * r!)
2 Method of Candidate Generation
Fk-1 * F1 Method
Fk-1 * Fk-1 Method
Maximal frequent itemset
An itemset is maximal frequent if it is frequent and none of its immediate supersets is frequent.
Closed Itemset
An itemset X is closed if none of its immediate supersets has the same support as the itemset X.