What is an average final score between a matchup?
for our league there are 10 stats (5 batting & 5 pitching) being tracked.  
batting:  runs, homers, rbis, steals and average
pitching: wins, saves, strikes, era and whip (walks and hits per inning pitched)
for every stat a team leads,  that team gets 1 point.  if both teams are tied in a stat no points are awarded.  
if you lead at the end of our matchup in runs, homers,  average, wins, strikes and era you get 6 points.  
then
if i lead in rbis, steals, saves and whip i get 4 points.  
for the week you beat me and will be awarded a win for the win column.  
at the end of the week if you and i are tied (5 stats you lead and 5 stats i lead) then our record will reflect a tie.  that is why there is win, loss and tie column on the teams front page.  
if i wrote this and you knew it all along then go  

 yourself.  
disclaimer::  don't worry ogre, the whip column doesn't represent how often jumbo  

 you per week.   
i know that didn't directly answer your question. most leagues i have played it has been 6 to 4.  
i rock at teh yahoos fantasy baseball.