moserware/PHPSkills — Issue #4: Error On calculateMatchQuality
Author: pkirk
Created: 2011-12-24 15:22:20+00:00
State: open

Looking at the paper's PDF
http://research.microsoft.com/pubs/67956/NIPS2006_0688.pdf (equation 7)
you swapped Sigma with Mu

This line below:
($totalPlayers*$betaSquared + $team1StdDevSquared + $team2SigmaSquared)
should be:
($totalPlayers*$betaSquared + $team1StdDevSquared + $team2StdDevSquared)

and so the "exp" part has a mirror error.