$10.$ Consider the following transaction dataset represented by a table:

TID Transaction

$1\{$I$2,$ I$3,$ I$4,$ I$5\}$

$2\{$I$1,$ I$3\}$

$3\{$I$2,$ I$3,$ I$5\}$

$4\{$I$1,$ I$4,$ I$5\}$

$5\{$I$1,$ I$2,$ I$4\}$

$6\{$I$3,$ I$5\}$

$($a$)$ What is the support count of the itemset $\{$I$2,$ I$4\}?$

$($b$)$ Compute the Kulczynski measure of the itemsets $\{$I$1,$ I$2\}$ and $\{$I$4\}.$

$($c$)$ Suppose that an itemset A has n items. How many subsets does A have? Why can this

be a problem for frequent itemset mining?

$($d$)$ Explain why frequent itemset mining is often a preliminary step in association rule

mining.