title: What is the normal value of Lift Ratio in Association Rules?
body: <p>I am currently using Apriori algorithm to find association rules, and i want to find the lift ratio of every rules that i got. From what i get, the lift ratio formula is</p>
  <p>confidence / expected_confidence =
  (frequency(a,b) / frequency(a)) / (frequency(b)/ total_transaction)</p>
  <p>When i use the formula, all my association rules have too high lift ratio (such as 9, 17, 20), is it that my formula wrong? or is it normal to have high lift ratio? because the terms of lift ratio is getting lift ratio &gt; 1, but i don't get any rules with lift ratio &lt; 1, so i thought i might be wrong on using the formula.</p>
  <p>Can anyone help me? thanks in advance.</p>