This allows you to work out the probability of any real-world event, Given the factors and each variable that plays in each factor.
Lets say that theres 100 students now you could say that their avarage number of interacrions being 8 for example then thats an average of 800 interactions, being in one interaction is 1 / 800 but in the real world students can be more shy or confident so lets say each student has an interaction amount between 4-12 so now there are possible combinations of interactions each student can be shy, 4,4,4, ... or confident, 12,12,12 ... and now since there are possible interacrion combinations the probability can be worked out with this calculator, P= 1/x^N in this case thats 1/9^100 (9 possible interaction varations for each student in the 100 student example)