A: [img=71x21]180394ecac44e9b.png[/img]
B: [img=71x21]180394ecb4a9a37.png[/img]
C: [img=88x25]180394ecbd060c4.png[/img]
D: [img=77x19]180394ecc5783f4.png[/img]
举一反三
- 设A、B是线性空间X的子空间，当它们满足（ ）时，X为A与B的直和. A: [img=71x21]180394ec4fdab06.png[/img] B: [img=71x21]180394ec5a26dbe.png[/img] C: [img=88x25]180394ec697b3d0.png[/img] D: [img=77x19]180394ec826debf.png[/img]
- 设[img=77x19]1802e2aa5a4095f.jpg[/img]，则E(X)=4，D(X)=4/3.
- 设随机变量X的概率密度为[img=172x58]1802fe3273041d3.png[/img]则使得F{X > a} = F{X < a}成立，则a为( ). A: 2-1/4 B: 21/4 C: 1/2 D: 1-2-1/4
- 已知随机变量X的分布函数为[img=136x49]1803b69024c8270.png[/img] ，则X的均值和方差分别为 A: E(X)=2, D(X)=4 B: E(X)=4, D(x)=2 C: [img=162x43]1803b6902cd8bfb.png[/img] D: [img=162x43]1803b69034d9ffd.png[/img]
- 设二维随机变量(X，Y)的协方差[img=106x43]1803b690addcf73.png[/img]，且D(X)=4，D(Y)=9，则X与Y的相关系数[img=28x18]1803b690b60844b.png[/img]为 A: [img=27x43]1803b690be8e24f.png[/img] B: [img=18x43]1803b690c71b6d7.png[/img] C: [img=9x43]1803b690cf6fffc.png[/img] D: 1
内容
- 0
设随机变量X服从均匀分布[img=71x21]17e447f6bc62456.png[/img],[img=51x20]17e447f6c9351a7.png[/img],若二维随机变量(X,Y)的联合分布函数为F(x,y),则[img=58x41]17e447f6d3c5f11.png[/img]= ____ .(用分数表示)
- 1
随机变量X的分布律如下表[img=210x86]17de6027b9f95df.png[/img]则D( X ) =（ ）． A: 7/8 B: 15/8 C: 71/64 D: 71/4
- 2
设随机变量X,Y有D(X)=4, D(Y)=9,[img=91x21]17e447e132da9ab.png[/img],则ρXY = ____
- 3
Which of the following propositions is false,set A = {x,x is an integer and[img=60x23]1803a1c6eebb7a3.png[/img]} ? ( ) A: [img=113x25]1803a1c6f77ce06.png[/img] B: [img=139x25]1803a1c7001fe79.png[/img] C: [img=51x22]1803a1c70863f61.png[/img] D: {x|x is an integer and |x| 4}[img=33x22]1803a1c711a7c63.png[/img]
- 4
Which of the following propositions is false,set A = {x,x is an integer and [img=60x23]1803a1c503ffa04.png[/img]} ? ( ) A: [img=113x25]1803a1c50cc3162.png[/img] B: [img=139x25]1803a1c514e60ea.png[/img] C: [img=51x22]1803a1c51dd52ef.png[/img] D: {x|x is an integer and |x| <4} [img=33x22]1803a1c525cf1bd.png[/img]