Posted by haifeng on 2011-05-27 09:17:42 last update 2018-05-28 14:48:29 | Answers (2) | 收藏
二项分布 $B(n,p)$
设随机变量 $X\sim B(n,p)$, 其分布律是
\[ P\{X=k\}=C_n^k p^k q^{n-k}, \quad k=0,1,2,\ldots,n, \quad q=1-p. \]
于是
\[ E(X)=np,\quad D(X)=npq. \]
