Definition: Frequent Itemset Item set a collection of one or more items Example: Milk, Bread, Diaper] K-itemset TD ltems e An itemset that contains k items Bread, milk Support count(o) Bread, diaper, beer, eggs Frequency of occurrence of an itemset 234 Milk, Diaper, Beer, Coke E.g. o(Milk, Bread, Diaper )=2 Bread, Milk, Diaper, Beer Bread, Milk, Diaper, Coke Support Fraction of transactions that contain an itemset E.g. s(Milk, Bread, Diaper) )=2/5 Frequent Itemset An itemset whose support is greater than or equal to a minsup threshold n Steinbach. Kumar Introduction to Data Mining 4/18/2004© Tan,Steinbach, Kumar Introduction to Data Mining 4/18/2004 ‹#› Definition: Frequent Itemset Itemset – A collection of one or more items ◆ Example: {Milk, Bread, Diaper} – k-itemset ◆ An itemset that contains k items Support count () – Frequency of occurrence of an itemset – E.g. ({Milk, Bread,Diaper}) = 2 Support – Fraction of transactions that contain an itemset – E.g. s({Milk, Bread, Diaper}) = 2/5 Frequent Itemset – An itemset whose support is greater than or equal to a minsup threshold TID Items 1 Bread, Milk 2 Bread, Diaper, Beer, Eggs 3 Milk, Diaper, Beer, Coke 4 Bread, Milk, Diaper, Beer 5 Bread, Milk, Diaper, Coke