Suppose you have a set of 200 videos, with 100 Yes(Like) and 100 No(Dislike).

You now have two choices of attributes to ask about:

A is a binary attribute. If you ask about attribute A you get two resulting sets, one with 80 Yes and 20 No; and the other with 20 Yes and 80 No.

B is a three-valued attribute. If you ask about attribute B, you get three resulting sets, one with X Yes and 50 No; the second with X Yes and 50 No; and the third with (1002X) Yes and 0 No.

Note that if X is 0, we definitely prefer Attribute B; if X is 50, we definitely prefer Attribute A. What is the largest value for X such that Attribute B is more informative than Attribute A?