However not all of these Worlds, are in fact habitated. Therefore the average population of the universe must be Zero. As anything divided by Zero is as next to nothing as makes no odds.
* You think you don't exist?
* I assume you want the word "density" in there somewhere.
* Check what "Therefore" means.
* Check your maths on what happens when you divide by zero. It does not approach zero.
If we assume that you actually do exist, then the population of the universe is at least 1. And we know that 1 divided by any number >0 is also >0. So as long as you exist, and the universe is not negative sized, the average population of the universe is greater than zero.