How to let views's sort criteria random equally I have two node content. I want to know which content is able to convince user to sign up.

I create a views block and two node contents. The views will randomly choose one node content and display.

At the views sort criteria, I choose global random, but it does not random equally. It choose option A more than option B. 

Question: How to let it choose random equally or alternate such as A,B,A,B,A,B..etc?
If you enable core Statistics module, you get some more filters in views:


Content statistics: Most recent view
Content statistics: Total views
Content statistics: Views today


You can select one of them, and sort ascending. So that it will always show the least recent viewed node, or least viewed node in all times, or least viewed node today, respectively which filter you've chosen.