设随机变量X~B（10，0.4），则X
答案:3 悬赏:30 手机版
解决时间 2021-04-01 17:45
- 提问者网友：椧運幽默
- 2021-04-01 07:10
设随机变量X~B（10，0.4），则X
最佳答案
- 五星知识达人网友：罪歌
- 2021-04-01 08:04
E(X) =np = 10(0.4)=4
D(X)=np(1-p) = 10(0.4)(0.6) = 2.4
D(X) =E(X^2) -[E(X)]^2
2.4 =E(X^2) -16
E(X^2)=18.4
D(X)=np(1-p) = 10(0.4)(0.6) = 2.4
D(X) =E(X^2) -[E(X)]^2
2.4 =E(X^2) -16
E(X^2)=18.4
全部回答
- 1楼网友：平生事
- 2021-04-01 10:01
D(x)=E(x^2)-[E(x)]^2
D(x)=np(1-p)=2.4
[E(x)]^2=(np)^2=16
E(x^2)=18.4
D(x)=np(1-p)=2.4
[E(x)]^2=(np)^2=16
E(x^2)=18.4
- 2楼网友：末日狂欢
- 2021-04-01 08:37
D(x)=E(x^2)-[E(x)]^2
D(x)=np(1-p)=2.4
[E(x)]^2=(np)^2=16
E(x^2)=18.4追问谢了！
D(x)=np(1-p)=2.4
[E(x)]^2=(np)^2=16
E(x^2)=18.4追问谢了！
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