This is essentially registered voters. Also, If I understand correctly, they weighted the poll (from the bottom of the first pdf) GOP/Dem/Ind 284/406/344. So the results they report are 406/284 = 1.43 times in favor of the Rats. This poll is complete and total BS.
CBS polls usually are. Actually most network and magazine polls are bad when they aren’t conducted through mainline pollsters.
That’s the point — the poll is favoring Dems, but it is still pretty good for McCain.
They are not called ‘See BS’ for nothing.