Prove that in the data of 6.1.4 there are no interesting association rules; i.e., the interest of…

Prove that in the data of  6.1.4 there are no interesting association rules; i.e., the interest of every association rule is 0.  If we use a triangular matrix to count pairs, and n, the number of items, is 20, what pair’s count is in a[100]?