People start with Yahoo! chess ratings of 1200. From there they fluctuate with results;
so: yes. Assume that the average Yahoo! chess rating is within the 1100-1300 range.
The above Yahoo! chess ratings information has NOTHING AT ALL WHAT-SO-EVER
to do with real and meaningful over-the-board ELO chess ratings at USCF and FIDE.
Don't be trying to convert a Yahoo! rating to a USCF rating by inventing some formula.
A player with a high Yahoo! chess rating assisted by their computer programs, hacks,
and otherwise cheating, might not ever win a game over the board on their own.
I've seen Yahoo! chess ratings of 3000. Just use Yahoo! chess for what it is, if at all.