s*********r
发帖数: 183 | 1 扔一枚硬币，以概率p是H。
求前2n-1次试验，至少有n次H的概率？有简单形式的答案吗？谢谢！ | c**********e
发帖数: 2007 | 2 For p=1/2, it is 1/2. For general p, there is probably not a simple
close form solution, unless you use normal approximation, which is
good when n is large. Of course, the binomial form expression is not
too complicated.
So the general solution, use binomial expression for small n and
normal expression for large n.
【在 s*********r 的大作中提到】
: 扔一枚硬币，以概率p是H。
: 求前2n-1次试验，至少有n次H的概率？有简单形式的答案吗？谢谢！
| h*****r
发帖数: 1052 | 3 is this a tail funcion for Binomial?
I think I have been asked about this question in an interview..
【在 c**********e 的大作中提到】
: For p=1/2, it is 1/2. For general p, there is probably not a simple
: close form solution, unless you use normal approximation, which is
: good when n is large. Of course, the binomial form expression is not
: too complicated.
: So the general solution, use binomial expression for small n and
: normal expression for large n.
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