Line Speed = fn (Line Stats)?

I've seen it said in various threads that with such-and-such line stats, like Line attenuation & Noise margin, you should be getting so-and-so line speed.

Can anyone tell me if there is a way of expressing Line Speed as a function of these Line Stats? Or point me to somewhere that can.

Try here:

http://www.kitz.co.uk/adsl/max_speed_calc.php

and www.farina1.com/adsl