In your diagram workspace,
rightclick the
Association node and click
Run.
In the
Confirmation window, click
Yes.
Click
Results in the
Run Status window.
In the
Results window,
select
ViewRulesRules Table from the main menu.
The
Rules Table displays information about
each rule that was created. This includes the confidence, support,
lift, number of occurrences, and the items in the rule. To explain
confidence, support, and lift, consider the rule A => B where A
and B each represent one product.

The support percentage for A =>
B is the percentage of all customers who purchased both A and B. Support
is a measure of how frequently the rule occurs in the database.

The confidence percentage for A
=> B is the percentage of all customers who purchased both A and
B, divided by the number of customers who purchased A.

The lift of A => B is a measure
of the strength of the association. For example, if the lift is 2
for A => B, then a customer who purchased A is twice as likely
than a customer chosen at random to purchase B.
Sort the
Rules
Table by
Support (%). Notice
that the top two rules are
heineken ==> cracker and
cracker
==> heineken, both with a support of 36.56%. This
indicates that 36.56% of all customers purchased beer and crackers
together.
The confidence for
heineken
==> cracker is 61%, which indicates that 61% of customers
who purchased Heineken
then purchased crackers. For the rule
cracker ==> heineken,
the confidence is 75%. This means that 75% of the customers who purchased
crackers then purchased Heineken.
Lift, in the context
of association rules, is the ratio of the confidence of a rule to
the expected confidence of the rule. The expected confidence is calculated
under the assumption that the left hand side of a rule is independent
from the right hand side of the rule. Consequently, lift is a measure
of association between the left hand side and right hand side of the
rule. Values that are greater than one represent positive association
between the left and right hand sides. Values that are equal to one
represent independence. Values that are less than one represent negative
association between the left and right hand sides.
Sort the
Rules
Table by
Lift. Notice that the
rule
ice_crea ==> coke has the greatest
lift. This indicates that customers who buy ice cream are 2.38 times
more likely to buy Coke than a customer chosen at random.
Close the
Results window.