Has it been found that there is any coleration between chess mentor ratings and standard play chess ratings?

I wondered about - from what I see (and have experienced) i would expect there is a correlation in that higher in one will mean higher in the other, but I think chess mentor ratings dont = real game ratings.

Ratings for live chess, online chess, over the board chess, and mentor chess will all be different, but i reckon stronger players will generally be higher on all of them. 

Great answer,thanks.