Association Rule is an unsupervised data mining function.
It finds rules associated with frequently co-occurring items, used for:
An 'association' is not a causality.
Finds items that tend to co-occur in the data and specifies the rules that govern their co-occurrence
Association models are built on a population of interest to obtain information about that population; they cannot be applied to separate data.
An association model returns rules that explain how items or events are associated with each other.
The association rules are returned with statistics that can be used to rank them according to their probability.