Today I finished completing the calculation of probability of assigning people with unordered sets.
Let's assume that we are going to pick up 3 people to be committees from a group of six.
First, we calculate how many ways of assigning people with ordered sets:
So it is
5 x 4 x 3 which equals 5!/3!, also equals N!/(N-n)!
then if the order doesn't matter, then we need to deduct the number that we triplely calculate it, since there are 6 ways of 3 people in arrangement, so we need to divide it, which is like:
5!/3!3!, which equals N!/(N-n)!n!.
Okay, I really think I have much clearer idea about binomial coefficient, awesome!!!
