finalPrep - Association Rules Why use Association Rules?...

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Unformatted text preview: Association Rules Why use Association Rules? Data Understanding Which attributes are strongly related? People who shop at home depot also shop at? Model Understanding Compare / contrast highest-scoring decile with lowest-scoring decile Can help to explain the behavior of complex models like neural networks Segmentation Cross marketing apriori algorithm Collect single item counts. Find large items. Find candidate pairs, count them => large pairs of items. Find candidate triplets, count them => large triplets of items, and so on Guiding principle : Every subset of a frequent item set has to be frequent Used to prune many candidate sets 2002 by D. C. St. Clair CS 404 Data Mining & Knowledge Discovery -- L8 21 Illustrating Apriori Principle Item Count Bread 4 Coke 2 Milk 4 Beer 3 Diaper 4 Eggs 1 Items (1-itemsets) Pairs (2-itemsets) Triplets (3-itemsets) Minimum Support = 3 Example from: R. Grossman, C. Kamath, And V. Kumar, Data Mining for Scientific And Engineering Applications Itemset Count {Bread,Milk} 3 {Bread,Beer} 2 {Bread,Diaper} 3 {Milk,Beer} 2 {Milk,Diaper} 3 {Beer,Diaper} 3 Itemset Count {Bread,Milk,Diaper} 3 {Milk,Diaper,Beer} 2 1. Find all item sets that have transaction support above minimum support The support of an item set is the number of transactions that contain the item set Items with minimum support are called large item sets 2. Use the large item sets to generate the rules For every large item set...
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This note was uploaded on 08/25/2011 for the course CPE 404 taught by Professor Merz during the Fall '09 term at Missouri S&T.

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finalPrep - Association Rules Why use Association Rules?...

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