4. Association Rules

Association Rules

With association rules, given a particular dataset, we try to establish a rule that is supported by the data (and with some confidence) suggests a logical inference. For example, people who purchase item $X$ may also purchase $Y$.

Let $X$ be an item-set, $X\to Y$ an association rule, and $T$ a set of transactions of a given database:

• The support value of $X$ with respect to $T$ is defined as the proportion of transactions which contains the item-set $X$.
• The confidence value of a rule, $X\to Y$ wrt. $T$ is the proportion of transactions that contains $X$ which also contains $Y$.

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