20春学期《概率论X》在线平时作业3

adminhan · 发表于 2020-8-8 19:00:17

设随机变量X1，X2，…Xn(n>1)独立分布，且其方差<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Arial','sans-serif'; BACKGROUND: white; COLOR: black; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">σ2>0.令随机变量Y=1/n(X1+X2…+Xn),则
A:D（X1+Y）=(n+2)/n<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Arial','sans-serif'; BACKGROUND: white; COLOR: black; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">σ2
B:D（X1-Y）=(n+1)/n<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Arial','sans-serif'; BACKGROUND: white; COLOR: black; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">σ2
C:cov(X1,Y)=<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Arial','sans-serif'; BACKGROUND: white; COLOR: black; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">σ2/n
D:cov(X1,Y)=<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Arial','sans-serif'; BACKGROUND: white; COLOR: black; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">σ2

如果F(x)是X的分布函数，它肯定满足下面哪一个性质？
A:对所有-∞＜x＜+∞，都有：1/2≤F(x)≤1；
B:F(x)是一个连续函数；
C:对所有a＜b，都有：F(a)＜F(b)；
D:对所有a＜b，都有：P{a＜X≤b}=F(b)-F(a)

<p style="TEXT-INDENT: -301.5pt; MARGIN: 0cm 0cm 0pt 312pt; mso-char-indent-count: -33.5; mso-line-height-alt: 0pt; punctuation-wrap: simple; mso-line-break-override: restrictions; mso-para-margin-left: 1.0gd" class="MsoNormal">若X与Y均相互独立且服从标准正态分布，<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">则<span style="FONT-FAMILY: "Times New Roman"; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">Z = X + Y<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">（<span style="FONT-FAMILY: "Times New Roman"; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">    <span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">）
A:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">服从<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">N<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">（<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">0<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">2<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">）
B:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">服从<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">N<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">（<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">0<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">1<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">）
C:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">服从<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">N<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">（<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">0<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，1.5<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">）
D:不一定服从正态分布

<span style="WIDOWS: 2; TEXT-TRANSFORM: none; BACKGROUND-COLOR: rgb(255,255,255); TEXT-INDENT: 30px; DISPLAY: inline !important; FONT: 14px/24px arial, 宋体, sans-serif; WHITE-SPACE: normal; ORPHANS: 2; FLOAT: none; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px"><span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">设<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">DX = 4<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">DY = 1<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，ρXY=0.6，<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">则<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">D(2X-2Y) = 
A:40
B:34
C:25.6
D:17,.6

设两个随机变量X与Y相互独立且同分布：P{X=－1}=P{Y=－1}=0.5，P{X=1}=P{Y=1}=0.5，则下列各式中成立的是
A:P{X=Y}=0.5
B:P{X=Y}=1
C:P{X+Y=0}=0.25
D:P{XY=1}=0.25

<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt">设<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt" lang="EN-US"><v:shapetype id="_x0000_t75" stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" o:preferrelative="t" o:spt="75" coordsize="21600,21600"> <v:stroke joinstyle="miter"></v:stroke><v:formulas><v:f eqn="if lineDrawn pixelLineWidth 0"></v:f><v:f eqn="sum @0 1 0"></v:f><v:f eqn="sum 0 0 @1"></v:f><v:f eqn="prod @2 1 2"></v:f><v:f eqn="prod @3 21600 pixelWidth"></v:f><v:f eqn="prod @3 21600 pixelHeight"></v:f><v:f eqn="sum @0 0 1"></v:f><v:f eqn="prod @6 1 2"></v:f><v:f eqn="prod @7 21600 pixelWidth"></v:f><v:f eqn="sum @8 21600 0"></v:f><v:f eqn="prod @7 21600 pixelHeight"></v:f><v:f eqn="sum @10 21600 0"></v:f></v:formulas><v:path o:connecttype="rect" gradientshapeok="t" o:extrusionok="f"></v:path><o:lock aspectratio="t" v:ext="edit"></o:lock></v:shapetype><v:shape style="WIDTH: 14.25pt; HEIGHT: 12.75pt" id="_x0000_i1025" o:ole="" type="#_x0000_t75"><v:imagedata o:title="" src="file:///C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\msohtml1\01\clip_image001.wmz"></v:imagedata></v:shape><span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt">表示<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt" lang="EN-US">10<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt">次独立重复射击命中次数，每次命中的概率为<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt" lang="EN-US">0.4<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt">，则E（X2）=
A:18.4
B:16.4
C:12
D:16

 甲，乙，丙三人独立地译一密码，他们每人译出此密码都是0.25，则密码被译出的概率为          <o:p></o:p>
A:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">1/4
B:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">1/64
C:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">37/64
D:<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US"> 63/64

设两个随机变量X和Y相互独立的同分布：P(X=-1)=P(Y=-1)=1/2，P(X=1)=P(Y=1)=1/2，则下列各式中成立的是（）
A:P(X=Y)=1/2
B:P(X=Y)=1
C:P(X+Y=0)=1/4
D:P(XY=1)=1/4

<img alt="" src="http://file.open.com.cn/itemdb/dbdx/gailvlun/test/12313918145311.1.jpg" /> 
A:6
B:22
C:30
D:41

<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">市场上某商品来自两个工厂，它们市场占有率分别为<span style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">60<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">％和<span style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">40<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">％，有两人各自买一件。 <span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">则买到的来自相同工厂的概率为 
A:0.52
B:0.48
C:0.24
D:0.36

<div>设X，Y是相互独立的两个随机变量，它们的分布函数分别为FX(x),FY(y),则Z = max {X,Y} 的分布函数是</div>
A:<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">FZ<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">（z）= max { FX(x),FY(y)};
B:<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">FZ<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">（z）= max { |FX(x)|,|FY(y)|}
C: FZ（z）= FX（x）·FY(y) 
D:<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">都不是

设离散型随机变量X的数学期望E(X)=2,则3X+2的数学期望是
A:4
B:5
C:7
D:8

从1,2,3,4,5五个数码中，任取3个不同数码排成三位数，求所得三位数为奇数的概率
A:0.3
B:0.4
C:0.5
D:0.6

<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">若随机变量<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">X<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">的数学期望与方差分别为<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">EX =1<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA" lang="EN-US">DX = 0.1<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">，根据切比雪夫不等式，一定有
A:P{-1<X<1}>=0.9
B:P{0<X<2}>=0.9
C:P{-1<X<1}<=0.9
D:P{0<X<2}<=0.9

<img alt="" src="http://file.open.com.cn/itemdb/dbdx/gailvlun/test/12313891034211.4.jpg" /> 
A:0.2
B:0.975
C:0.25
D:0.375

<div align="left">对于任意两个随机变量X和Y，若E（XY）=E(X)E（Y）则            </div>
A:<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">D<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">（XY）=D（X）D（Y）
B:<div>D（X+Y）=D（X）+D（Y）</div>
C:<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">X和Y独立 
D:<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">X<span style="FONT-SIZE: 10.5pt; FONT-FAMILY: 宋体; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes">和Y不独立

<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">设随机变量<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">X<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的方<span style="FONT-FAMILY: 宋体; FONT-SIZE: 9pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">差<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 9pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">DX =<span style="FONT-FAMILY: Arial; BACKGROUND: white; COLOR: black; FONT-SIZE: 9.5pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">σ2，则D（ax+b）=
A:a<span style="FONT-FAMILY: Arial; BACKGROUND: white; COLOR: black; FONT-SIZE: 9.5pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">σ2+b
B:a2<span style="FONT-FAMILY: Arial; BACKGROUND: white; COLOR: black; FONT-SIZE: 9.5pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">σ2+b
C:<span style="FONT-FAMILY: Arial; BACKGROUND: white; COLOR: black; FONT-SIZE: 9.5pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">aσ2
D:a2<span style="FONT-FAMILY: Arial; BACKGROUND: white; COLOR: black; FONT-SIZE: 9.5pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体" lang="EN-US">σ2

 甲，乙，丙三人各自独立地向一目标射击一次，三人的命中率分别是0.5，0.6，0.7，则目标被击中的概率为<o:p></o:p>
A:0.92
B:0.94
C:0.95
D:0.90

设当事件A与B同时发生时，事件C必发生，则
A:P(C)<=P(A)+P(B)
B:P(C)>=P(A)+P(B)-1
C:P(C)=P(AB)
D:P(C)=P(A)P(B)

在某学校学生中任选一名学生,设事件A:选出的学生是男生”;B选出的学生是三年级学生"。则P(A|B)的含义是：
A:选出的学生是三年级男生的概率
B:已知选出的学生是三年级的，他是男生的概率
C:已知选出的学生是男生，他是三年级学生的概率
D:选出的学生是三年级的或他是男生的概率

已知随机变量X和Y，则下面哪一个是正确的
A:E(X+Y)=E(X)+E(Y)
B:D(X+Y)=D(X)+D(Y)
C:E(XY)=E(X)E(Y)
D:D(XY)=D(X)D(Y)

设离散型随机变量X的分布列为P{X=i}=a|N,i=1,2,...,N  则a=
A:0
B:1
C:2
D:3

已知A包含于B，P(A)=0.2，P(B)=0.3，求P(AB)=( )
A:0.1
B:0.2
C:0.3
D:0.4

<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-bidi-font-family: 'Times New Roman'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes"> 将C,C,E,E,I,N,S等7个字母随机的排成一行，那末恰好排成英文单词SCIENCE的概率
A:1/7!
B:1/1260
C:5!/7!
D:1/640

<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt">设X<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt">与<span style="FONT-FAMILY: 'Times New Roman'; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-fareast-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt" lang="EN-US">Y<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-font-kerning: 1.0pt; mso-bidi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-size: 12.0pt">独立，且EX=EY=0，DX=DY=1，E(X+2Y)2=(   )
A:2
B:3
C:5
D:6

设某件事件发生的概率为p，乘积p(1－p)能衡量此事件发生的不确定性，特别得，当p＝0.5时，不确定性最大。
A:错误
B:正确

利用一个随机事件的频率(比例)能够求出概率的一个精确值。
A:错误
B:正确

甲、乙二人做如下的游戏：从编号为1到20的卡片中任意抽出一张，若抽到的数字是3的倍数，则甲获胜；若抽到的数字是5的倍数，则乙获胜，此时这个游戏对甲、乙双方是公平的。
A:错误
B:正确

抛一个质量均匀的硬币10次，则出现8次正面的概率大于2次正面的概率。
A:错误
B:正确

主观概率指的是对于不能做重复试验的随机事件，人们各自给出的对这个事件发生的相信程度。
A:错误
B:正确

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20春学期《概率论X》在线平时作业3

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