Who knows, it looks like a lot of confusion.
I have seen pages rank number 1 for a term that is all due to anchor text used in the incoming link (natural organic links) from respected writers (sites that have
PR) and the page that ranked number 1 for that term had ZERO PAGE RANK !!!
So does Page Rank determine everything, NO, is it a factor in ranking along with 100 + other components Google uses, YES.
Will Google tell you how they rank sites or how much weight Page Rank has versus other factors, NO !