Basic Concepts: Frequent Patterns and Association rules Transaction-id Items boug Itemset X={X1…,} A.B. D Find all the rules x>with minimum 20 A.C. D support and confidence 30 A,DE pport s, probability that a 40 B,EF transaction contains xu y 50 B, C,,EF confidence, c conditional Customer Customer probability that a transaction DUVS DO buys diaper having X also contains r Let supmin=50%, COl 50% Freg. Pat :A: 3, B: 3, D 4 E: 3, AD: 3y Association rules. Customer A→D(60%,100% buys beer D→A(60%,75%) February 4, 2021 Data Mining: Concepts and TechniquesFebruary 4, 2021 Data Mining: Concepts and Techniques 6 Basic Concepts: Frequent Patterns and Association Rules ◼ Itemset X = {x1 , …, xk} ◼ Find all the rules X → Y with minimum support and confidence ◼ support, s, probability that a transaction contains X  Y ◼ confidence, c, conditional probability that a transaction having X also contains Y Let supmin = 50%, confmin = 50% Freq. Pat.: {A:3, B:3, D:4, E:3, AD:3} Association rules: A → D (60%, 100%) D → A (60%, 75%) Customer buys diaper Customer buys both Customer buys beer Transaction-id Items bought 10 A, B, D 20 A, C, D 30 A, D, E 40 B, E, F 50 B, C, D, E, F