This forum needs a sticky

[Beavis68]

Explain what C(x,y) and x! mean.


I always forget.

[uuDevil]

C(x,y)=x!/(y!*(x-y)!}

This is the number of combinations of x things taken y at a time.

E.G. the number of ways to be dealt pocket aces in Hold'em is C(4,2)=4!/(2!*(4-2)!)=24/4=6 ways

x!= x*(x-1)*(x-2)*...3*2*1

E.G. 4!=4*3*2*1=24

[alThor]

A sticky for FAQ's would be a good idea. The simplest would be to provide links to previous threads that discuss:

combinations/permutations

inclusion-exclusion

various ROR threads

Monty Hall

Confidence intervals for win rates, etc. / Sample size

others? And please provide suggested links. Multiple links per topic might also be reasonable.

alThor

[tpir90036]

BruceZ gave me a good explanation of inclusion-exclusion back in the day in this thread (http://archiveserver.twoplustwo.com/showflat.php?Cat=0&Number=416981). Make sure you read all the way to the end though as he made a revised response.

-tpir