Repetitions of a simulation

Repeating a simulation and observing the variability in the results can give insight into the randomness of the system's behaviour.

Model for sport league

Consider a sports league of 10 teams in which each team plays each other twice and:

 Points from a match =    3  if team wins
 1  if team draws
0  if team loses

We will model the league with a simple model for the results of individual matches. In it, team A has over twice the probability of winning than losing, but all other teams are equally matched.

Simulation

This model can be used to randomly generate the results of all 90 matches in the league.

Repeating the simulation 100 times gives the following results:

Despite team A being so much better than the other teams, the simulation shows that it has little more than 50% chance of ending the season on top of the league.