question: public Object2DoubleOpenHashMap < IntRBTreeSet > confidenceMap ( ) { List < ItemSet > itemSets = learn ( ) ; Object2DoubleOpenHashMap < IntRBTreeSet > confidenceMap = new Object2DoubleOpenHashMap < > ( itemSets . size ( ) ) ; for ( ItemSet itemSet : itemSets ) { IntRBTreeSet itemSetCopy = new IntRBTreeSet ( itemSet . items ) ; confidenceMap . put ( itemSetCopy , itemSet . support / ( double ) setCount ) ; } return confidenceMap ; }
target:  Returns a map of associations and their confidence, where confidence is support for the itemset (that is, the number of times it appears in the input data) divided by the total number of sets (i.e., the percentage of input sets where it appears.