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Flashcards in Association rules Deck (10)
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1

Support of a rule

How often do the LHS and RHS appear together

2

What is confidence

Given LHS, how often do we see RHS

3

What is lift

How often does LHS appear with RHS, compared to what chance would predict?

4

Confidence (X->Y)

n(X & Y) / n(X)

5

Is confidence symmetric

No

6

Lift formula (X->Y)

c(X->Y)/s(Y)
s(X&Y)/s(X) x s(Y)

7

Interpret lift (X->Y) = 5

Shoppers who buy X are 5x (500%) more likely to buy Y than the average shopper

8

Lift = 1 interpretation

Indicates almost no correlation
Events seem independent

9

Lift > 1 interpretation

Positive correlation
Cooccurrence is more likely than chance
Complementary products that are often bought together

10

Lift <1

Indicates negative correlation - co-occurance is less likely than chance
Customers who buy one item (or a given item set) are less likely (than average) to purchase the other

Substitutes