Guild Wars uses the ELO rating. Fine.
According this article http://gw.gamewikis.org/wiki/Rating , the correct formula to calculate the probability of winning is this one (using brackets ): p = 1/(1+(10((x-y)/400) where X is the enemy, and Y is your rating.
When I use this formula, to calculate the probability to win of a guild of my alliance ( 1111 rating ) and our guild ( 1125 rating ), I get a probability of 1.5384 . As far as I know, probabilities should be between 0 and 1 right? Any numbercruncher wanting to help here?
I'm creating some quick program to calculate our odds in a guild battle, how many points we win/lose etc. But it seems this formula is flawed, or I did something wrong.
EDIT stupid me...the exact formula : p = 1/(1+(10^((x-y)/400)
The probability now is 0.52, wich is normal.
