Question 3

A transaction database is a set of transactions completed in a supermarket database. Each transaction is a set of items. For example, consider the following transaction database. It contains 5 transactions (t1, t2, ..., t5) and 5 items (1,2, 3, 4, 5). For example, the first transaction represents the set of items 1, 3 and 4. It is important to note that an item is not allowed to appear twice in the same transaction and that items are assumed to be sorted by lexicographical order in a transaction.

Transaction id	Items
t1	{1, 3, 4}
t2	{2, 3, 5}
t3	{1, 2, 3, 5}
t4	{2, 5}
t5	{1, 2, 3, 5}

What is the output of the Apriori algorithm run on the previous transaction database with a minimum support of 40 % (2 out of 5 transactions)? (15 marks)