20春学期《概率论》在线平时作业2

adminhan

<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">如果</span><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><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">与</span><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">Y</span><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">满足</span><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(X+Y) = D(X-Y), </span><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>
A:<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><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">与</span><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">Y</span><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">独立</span>
B:<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"><h1 style="PADDING-BOTTOM: 0px; WIDOWS: 2; TEXT-TRANSFORM: none; BACKGROUND-COLOR: rgb(255,255,255); TEXT-INDENT: 0px; MARGIN: 0px 0px 5px; PADDING-LEFT: 0px; PADDING-RIGHT: 0px; FONT: bold 16px/26px 'Microsoft YaHei', SimHei, arial; WHITE-SPACE: normal; ORPHANS: 2; LETTER-SPACING: normal; COLOR: rgb(51,51,51); WORD-BREAK: break-all; WORD-SPACING: 0px; PADDING-TOP: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px" class="mb-5" accuse="qTitle">&rho;_XY= 0</h1></span>
C:<span style="FONT-FAMILY: &quot;Times New Roman&quot;; 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-DY = 0<span style="mso-spacerun: yes">&nbsp; </span></span>
D:<span style="FONT-FAMILY: &quot;Times New Roman&quot;; 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+DY = 0<span style="mso-spacerun: yes">&nbsp; </span></span>

<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X~N(2，4),则D（0.5X）=</span>
A:1
B:2
C:3
D: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" lang="EN-US">若P(A)=0,B</span><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">为任一事件，则</span>
A:A为空集
B:B包含A
C:<p>A,B相互独立</p>
D:A,B互不相容

<p>把4个球随机投入四个盒子中，设X表示空盒子的个数，则P(X=0)=( )</p>
A:6|64
B:36|64
C:21|64
D:1|64

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt -0.1pt; mso-para-margin-left: -.01gd"><span style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">甲乙二人进行桌球比赛，每局甲胜的概率为</span><span lang="EN-US" style="FONT-SIZE: 12pt"><font face="Times New Roman">1/3</font></span><span style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，乙胜的概率为</span><span lang="EN-US" style="FONT-SIZE: 12pt"><font face="Times New Roman">2/3</font></span><span style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，三局两胜，若记</span><em><span lang="EN-US" style="FONT-SIZE: 12pt; mso-bidi-font-style: normal"><font face="Times New Roman">X</font></span></em><span style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">为比赛的局数，则</span><em><span lang="EN-US" style="FONT-SIZE: 12pt"><font face="Times New Roman">EX</font></span></em><span style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">＝</span><u><span lang="EN-US" style="FONT-SIZE: 12pt"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;&nbsp; </span><o:p></o:p></font></span></u></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-pagination: widow-orphan" align="left"><span lang="EN-US" style="FONT-SIZE: 12pt"><font face="Times New Roman"><o:p></o:p></font></span></p>
A:<font size="3"><font face="Times New Roman">&nbsp;22/9<span style="mso-spacerun: yes">&nbsp;</span></font></font>
B:<p><st1:chmetcnv w:st="on" unitname="C" sourcevalue="3" hasspace="True" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">3</span></st1:chmetcnv></p>
C:2
D:&nbsp;2/3

<span style="FONT-FAMILY: 宋体; FONT-SIZE: 10.5pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-font-kerning: 1.0pt; mso-no-proof: yes; mso-bidi-font-family: 'Times New Roman'">一射手对同一目标独立地进行四次射击，若至少命中一次的概率为80/81，则该射手的命中率为</span>
A:1/3
B:2/3
C:1/6
D:1/4

<p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; mso-char-indent-count: -1.5"><font face="宋体" size="3">随机变量<em><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体">X</span></em>与<em><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体">Y</span></em>服从二元正态分布<span lang="EN-US">N(2,-3,25,36,0.6),</span>则随机变量<em><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-family: 宋体">X</span></em>服从（）。</font></p><p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; mso-char-indent-count: -1.5"><font size="3"><span lang="EN-US" style="FONT-FAMILY: &quot;Times New Roman&quot;"><em style="mso-bidi-font-style: normal"></em></span></font><u><span lang="EN-US"><o:p></o:p></span></u></p>
A:<p style="MARGIN-LEFT: 18pt; TEXT-INDENT: -18pt; mso-char-indent-count: -1.5"><font size="3"><em style="mso-bidi-font-style: normal"><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'">N(</span></em><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'">2, -3<em style="mso-bidi-font-style: normal">)</em></span><span lang="EN-US"><font face="宋体"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span><span style="mso-spacerun: yes">&nbsp;</span></font></span></font></p>
B:&nbsp;<em style="mso-bidi-font-style: normal"><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'">N(</span></em><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'">2, 36<em style="mso-bidi-font-style: normal">)</em></span><span lang="EN-US"><font face="宋体"><span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></font></span>
C:&nbsp;<em style="mso-bidi-font-style: normal"><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'">N(</span></em><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'">-3</span><span style="mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'"><font face="宋体">，</font></span><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'"> 25<em style="mso-bidi-font-style: normal">)</em></span><span lang="EN-US"><font face="宋体">&nbsp;</font></span><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'"><em style="mso-bidi-font-style: normal"><span style="mso-spacerun: yes">&nbsp;</span></em></span>
D:<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: &quot;Times New Roman&quot;; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA"><em>N(</em></span><span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: &quot;Times New Roman&quot;; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">2, 25<em style="mso-bidi-font-style: normal">)</em></span>

<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><span lang="EN-US" style="FONT-SIZE: 12pt"><font face="Times New Roman"><span style="mso-spacerun: yes"><img height="41" width="402" alt="" src="http://file.open.com.cn/ItemDB/43587/73591776-87af-46ee-817a-a402522ea5c0/2009108114439910.JPG" />&nbsp;&nbsp;&nbsp;&nbsp; </span><u><o:p></o:p></u></font></span></p>
A:<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><font size="3"><span lang="EN-US"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp; </span><em style="mso-bidi-font-style: normal">N(</em>0, 5<em style="mso-bidi-font-style: normal">)</em><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></font></span></font></p>
B:<font size="3"><font face="Times New Roman">&nbsp;<span style="mso-spacerun: yes">&nbsp; </span><em style="mso-bidi-font-style: normal">N(</em>5, 5<em style="mso-bidi-font-style: normal">)</em><span style="mso-spacerun: yes">&nbsp;&nbsp;</span></font></font>
C:<font size="3"><font face="Times New Roman">&nbsp; <em style="mso-bidi-font-style: normal">N(</em>5</font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，</span><span lang="EN-US"><font face="Times New Roman"> 25<em style="mso-bidi-font-style: normal">)</em> </font></span></font>
D:<font size="3"><font face="Times New Roman"><span style="mso-spacerun: yes">&nbsp;</span><em style="mso-bidi-font-style: normal"><span style="mso-spacerun: yes">&nbsp; </span>N</em></font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">（</span><span lang="EN-US"><font face="Times New Roman">5, 1<em style="mso-bidi-font-style: normal">)<o:p></o:p></em></font></span></font>

<p><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">一颗均匀骰子重复掷</span><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><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，则</span><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><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">次中点数</span><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">3</span><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">平均出现的次数为<u>　　　</u></span></p>
A:4/3
B:5/3
C:10/3
D:7/6

<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">袋中有<span lang="EN-US">50</span>个乒乓球，其中<span lang="EN-US">20</span>个黄的，<span lang="EN-US">30</span>个白的，现在两个人不放回地依次从袋中随机各取一球。则第二人取到黄球的概率是</span>
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; mso-no-proof: yes" lang="EN-US">1/5 </span>
B:2/5
C:3/5
D:4/5

设两个随机变量X和Y的期望分别是6和3，则随机变量2X－3Y的期望是
A:6
B:3
C:12
D:21

<p><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">设在一次试验中事件</span><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">A</span><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">发生的概率为</span><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">P,</span><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">现重复进行</span><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">n</span><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">次独立试验</span><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">,</span><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">则事件</span><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">A</span><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">至多发生一次的概率为</span></p>
A:1-Pⁿ
B:Pⁿ
C:1-（1-P）ⁿ
D:(1-P)ⁿ+nP(1-P)^n-1

<div><font size="2">若X<span>～N（u₁，</span>_^&sigma;^₁2)^，Y<span>～N（u₂，_^&sigma;2²</span>）那么（<span>X，Y）的联合分布为</span></font></div>
A:<p><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">二维正态，且</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Tahoma','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-no-proof: yes; mso-fareast-font-family: 宋体">&rho;</span>=0<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"> </span></p>
B:<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">二维正态，且</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Tahoma','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-no-proof: yes; mso-fareast-font-family: 宋体">&rho;</span><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">不定</span>
C:&nbsp;未必是二维正态<span>&nbsp;</span>
D:<div>以上都不对</div>

设随机变量X服从正态分布N（5,4）.c使得P{X&gt;c}=P{X&lt;c}，则c=（）
A:6
B:5
C:4
D:3

<div>设X～N(&mu;，&sigma;2 )其中&mu;已知，&sigma;2未知，X₁，X_2&nbsp;_，X₃&nbsp;&nbsp;&nbsp; 样本，则下列选项中不是统计量的是<u>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </u>&nbsp;&nbsp;&nbsp;</div>
A:<span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 'Arial','sans-serif'; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">X₁+X_2&nbsp;+X₃&nbsp;&nbsp;</span>
B:<span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 'Arial','sans-serif'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes; mso-fareast-font-family: 宋体">max(X₁</span><span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial">，</span><span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 'Arial','sans-serif'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes; mso-fareast-font-family: 宋体">X_2&nbsp;</span>_{<span style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-bidi-font-family: Arial; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial">，</span>}<span lang="EN-US" style="FONT-SIZE: 9pt; FONT-FAMILY: 'Arial','sans-serif'; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes; mso-fareast-font-family: 宋体">X₃&nbsp;&nbsp;)</span><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"> </span>
C:_{<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Arial','sans-serif'; BACKGROUND: white; COLOR: #333333; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes; mso-fareast-font-family: 宋体">&sum;</span>Xi}<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Arial','sans-serif'; BACKGROUND: white; COLOR: #333333; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes; mso-fareast-font-family: 宋体">2_/&nbsp;</span>_{<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Tahoma','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-no-proof: yes; mso-fareast-font-family: 宋体">&sigma;2</span>}<span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Tahoma','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-no-proof: yes; mso-fareast-font-family: 宋体">&nbsp;</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; FONT-FAMILY: 'Arial','sans-serif'; BACKGROUND: white; COLOR: #333333; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-no-proof: yes; mso-fareast-font-family: 宋体">&nbsp;</span>
D:<div>X₁-u</div>

<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><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><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><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><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><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">&sigma;²，则D（ax+b）=</span>
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">&sigma;²+b</span>
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">&sigma;²+b</span>
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">a&sigma;²</span>
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">&sigma;²</span>

设X、Y的联合密度函数是p(x，y)，则把p(x，y)对x积分将得到：
A:0；
B:1；
C:Y的分布函数；
D:Y的密度函数。

&nbsp; <span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">从</span><span style="FONT-SIZE: 12pt" lang="EN-US">1</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，</span><span style="FONT-SIZE: 12pt" lang="EN-US">2</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，&hellip;&hellip;，</span><span style="FONT-SIZE: 12pt" lang="EN-US">9</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">这九个数中，随机抽取</span><span style="FONT-SIZE: 12pt" lang="EN-US">3</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">个不同的数，则这</span><span style="FONT-SIZE: 12pt" lang="EN-US">3</span><span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">个数的和为偶数的概率是</span><span style="FONT-SIZE: 12pt" lang="EN-US">( )</span>
A:&nbsp;11/21<span style="mso-spacerun: yes">&nbsp;&nbsp; </span>
B:1/<st1:chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="True" sourcevalue="2" unitname="C" w:st="on">2<span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;</span></st1:chmetcnv><span style="mso-spacerun: yes"> </span>
C:5/9<span style="mso-spacerun: yes">&nbsp;&nbsp;&nbsp;&nbsp;</span>
D:5/14

一袋子中装有6只黑球，4个白球，又放回地随机抽取3个，则三个球同色的概率是
A:0.216
B:0.064
C:0.28
D:0.16

<img alt="" src="http://file.open.com.cn/itemdb/dbdx/gailvlun/test/12313932939372.2.jpg" />&nbsp;
A:6
B:5
C:2
D:3