In probability theory and statistics, the Poisson distribution, is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time if these events occur with a known average rate and independently of the time since the last event.
In English, if we know the average number of goals scored in a fixed interval of time (let-s say 90 minutes) the Poisson distribution give us the probability to be scored 0,1,2,3,4,...goals in the same interval of times.
In order to access Poisson calculator:
1. select "goals scored" for the both teams on the right parameters panel;
2. click the "REFRESH" button;
3. select a game in the main table;
4. click the "Poisson calculator for selected game" button.
We can see that Freiburg scored this season at home 2.846 goals/game since Karlsruhe scored away 0.846 goals/game.
Now click on the "Poisson calculator for selected game" button.
On the upper rows will see the probability to be scored a specific number of goals for each team. The most probable number of goals for Fraiburg is 2 (23.5% probability) and the most probable numbers of goals for the away team is 0 (42.9%).
Based on this distribution the system will calculate the probability for various type of results: correct score, over under, Asian handicap results...
The period of time you calculate the average number of goals have to be find after testing different values.