The Simplest Association Rules
Item sets are interesting. Association rules transform the item sets into rules. This section starts the discussion of association rules by calculating the proportion of orders that have a given product. These are the simplest, most basic type of association rule, one where the “if” clause is empty and the “then” clause contains one product: Given no information, what is the probability that a given product is an order? This idea of “zero-way” association rules is useful for two reasons. First, it provides a simple introduction to the ideas and terminology. Second, this overall probability is important for assessing more complex rules.
Associations and Rules
An association is a group of products that appear together—typically in an order, but the hierarchy could be at any level. The word “association” implies that the products have a relationship with each other based on the fact that they are...