Association Rule: Numerical Problem

 

Question:

Consider the confidence values of tree association rules as follows:

c1 =Conf(A→B)

c2 = Conf(A → BC)

c3 = Conf(AC → B)

What relationship can you draw among c1, c2 and c3?

Answer:

$c_1 = \text{Conf}(A \rightarrow B)$:

$$c_1 = \frac{\text{Support}(A \cup B)}{\text{Support}(A)}$$

$c_2 = \text{Conf}(A \rightarrow BC)$:

$$c_2 = \frac{\text{Support}(A \cup B \cup C)}{\text{Support}(A)}$$

$c_3 = \text{Conf}(AC \rightarrow B)$:

$$c_3 = \frac{\text{Support}(A \cup C \cup B)}{\text{Support}(A \cup C)}$$