Mining Strong Association Rules in Transaction DBs

• Measurement of rule strength in a transaction DB.

A ® B [support, confidence]

support = Prob(A È B) =

confidence = Prob(B|A) =

• We are often interested in only strong associations, i.e.

support ³ min_sup and confidence ³ min_conf.

• Examples.

milk ® bread [5%, 60%].

tire Ù auto_accessories ® auto_services [2%, 80%].

#_of_trans_containing_all_the_items_in A È B

total_#_of_trans

#_of_trans_that_contain_both A and B

#_of_trans_containing A

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