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-   -   This forum needs a sticky (http://archives2.twoplustwo.com/showthread.php?t=402304)

Beavis68 12-20-2005 08:16 PM

This forum needs a sticky
 
Explain what C(x,y) and x! mean.


I always forget.

uuDevil 12-20-2005 08:49 PM

Re: This forum needs a sticky
 
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 [edit]pocket aces in Hold'em [/edit] 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 12-21-2005 12:20 PM

Re: This forum needs a sticky
 
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 12-21-2005 06:10 PM

Re: This forum needs a sticky
 
BruceZ gave me a good explanation of inclusion-exclusion back in the day in this thread. Make sure you read all the way to the end though as he made a revised response.

-tpir


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