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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 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

Monty Hall

Confidence intervals for win rates, etc. / Sample size

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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