I am not a statistician, but I think something that needs to be taken into account when considering the numbers that you have presented, is that the more time that passes, between when a post is made and the present, the more likely it is that a:

 - post will be voted on; and
 - question will be answered

This is because the more times a post is viewed, the more likely it is that 1 to many people will take an action on it.

Of the four sets of statistics that you have presented, I think only the second one will not be heavily correlated with time since posting.