- #1
Gerenuk
- 1,034
- 5
Hello!
Is there a closed form expression or a good estimate for the probability that a binomial distribution yield the average np or less. Basically I'm asking for a good way to evaluate
[tex]
P=\sum_{k=0}^{np} \begin{pmatrix} n\\ k
\end{pmatrix} p^k(1-p)^{n-k}
[/tex]
I just figured that for the simplified case [itex]p=\frac{1}{n}[/itex] this probability converges to 63% for large n. What about more general cases?
Is there a closed form expression or a good estimate for the probability that a binomial distribution yield the average np or less. Basically I'm asking for a good way to evaluate
[tex]
P=\sum_{k=0}^{np} \begin{pmatrix} n\\ k
\end{pmatrix} p^k(1-p)^{n-k}
[/tex]
I just figured that for the simplified case [itex]p=\frac{1}{n}[/itex] this probability converges to 63% for large n. What about more general cases?
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