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Q: Probability of getting r OR MORE events in n tries? ( No Answer,   2 Comments )
Question  
Subject: Probability of getting r OR MORE events in n tries?
Category: Science > Math
Asked by: bernhardd-ga
List Price: $2.00
Posted: 27 Feb 2006 00:28 PST
Expires: 29 Mar 2006 00:28 PST
Question ID: 701390
What is the formula for the probability of getting r OR MORE (not
exactly) positive events for n tries?

The formula for getting the probability of r events after n tries is:
P(r|n) = (n!/r!(n-r)!)*p^r*q*(n-r), where q = 1.0-p. For the case of q
= p = 0.5 we get the formula (n!/r!(n-r)!)(1/2^n).

But this is the exact number for r events. I want to know the formula
for r or more events (up to n). In other words, there may be more then
r events. What is the total probability to get r OR MORE events given
n tries?
Answer  
There is no answer at this time.

Comments  
Subject: Re: Probability of getting r OR MORE events in n tries?
From: carryou-ga on 27 Feb 2006 18:53 PST
 
1 - probability of getting (r-1) in n tries.
My reasoning is intuitive rather than mathematical, hence am offering
no explanation. Eager to see how the reasoning for this turns out
Carryou
Subject: Re: Probability of getting r OR MORE events in n tries?
From: kottekoe-ga on 27 Feb 2006 19:35 PST
 
The answer is equation 3 of the Mathworld article on the binomial
distribution. It is expressed in terms of the incomplete beta
function. For your case, plug (r-1) in for n in that equation.

http://mathworld.wolfram.com/BinomialDistribution.html

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