欧阳老师 发表于 2017-11-14 19:54:54

西南大学网院17秋[0264]概率论在线作业及答案

0264
1、设二维随机向量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSd5d2ccd3b_144107c739e_OUL"/>的概率密度为　　<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSd5d2ccd3b_144107cba32_OUL"/>则（）.西南大学网院答案请咨询微信或QQ515224986

    k=3
    k=4
    k=7
    k=12
参考答案：k=12；
2、下列函数中，()可以作为连续型随机变量的分布函数.
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSd5d2ccd3b_1441071a8db_USL&rc=QyEFx8H7XhxqbcYLYT9TMA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSd5d2ccd3b_1441072128d_USL&rc=QyEFx8H7XhxqbcYLYT9TMA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSd5d2ccd3b_14410726f93_USL&rc=QyEFx8H7XhxqbcYLYT9TMA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSd5d2ccd3b_1441072c150_USL&rc=QyEFx8H7XhxqbcYLYT9TMA%3D%3D"/>
参考答案：<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSd5d2ccd3b_1441072128d_USL&rc=QyEFx8H7XhxqbcYLYT9TMA%3D%3D"/>；
3、已知二维随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a6d387c_OUL"/>的联合分布律为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a6e4d9a_OUL"/>则().
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a748380_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a74de31_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a75430b_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a759dac_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
参考答案：<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a759dac_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>；
4、设两个相互独立的随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a668fb3_OUL"/>，<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a66dcc5_OUL"/>，<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a670349_OUL"/>，<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a6737b5_OUL"/>,则（）。
    A.<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSo5d2ccd3b_14462283059_OUL"/>
    B.<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSo5d2ccd3b_1446228a98e_OUL"/>
    C.<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSo5d2ccd3b_1446228f15d_OUL"/>
    D.<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSo5d2ccd3b_1446229e704_OUL"/>
5、设随机变量X~<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a615b7f_OUL"/>,且EX=3,<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a61c96c_OUL"/>,则P(-1&lt;X&lt;1)=().
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a640545_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a6458bd_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a64af3b_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a6508e0_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
6、设随机变量X服从二项分布<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a008eec_OUL"/>,由切比雪夫不等式有().
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a0291f9_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a02fbc6_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a035fda_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_1440a03b962_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
7、对于任意两个随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409fb1705_OUL"/>，下面（）说法与协方差<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409fb6954_OUL"/>不等价。
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409fd97c6_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409fdfa03_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409fe5f48_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409fec03c_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
8、设<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409f5c500_OUL"/>，则必有（）。
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409f7eca7_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409f84a46_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409f8b17b_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409f913a6_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
9、两人相约7点到8点在某地会面，先到者等候另一人20分钟既可离去，则这两个人能会面的概率为（）.
    0
    4/9
    5/9
    1
10、设随机变量序列<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e2ecca_OUL"/>，对应的分布函数列为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e333a6_OUL"/>，特征函数列为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e35bd9_OUL"/>，随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e38246_OUL"/>对应的分布函数为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e3c32a_OUL"/>，特征函数为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e3e760_OUL"/>，则下面不成立的为（）。
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e6cb77_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e72bea_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e79316_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409e7f050_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
11、设随机变量X~B(n,p),且E(X+1)=6,D(X+1)=4,则n=().
    10
    20
    25
    50
12、下面是几个随机变量的概率分布，其中期望不存在的为（）。
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409dc6523_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409dce3cc_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409dd4510_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409dda117_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>
13、设随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409d62973_OUL"/>的分布函数为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409d65d24_OUL"/>则其中常数为（）。
    A=1,B=-1
    A=-1,B=1
    A=1,B=1
    A=-1,B=-1
14、对事件A、B，下列说法正确的是（）.
    若A与B互不相容，则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409d338cf_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>也互不相容
    若A与B相容，则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409d3fc51_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>也相容
    若A与B互不相容，则A与B相互独立
    A与B相互独立，则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSe5d2ccd3b_14409d50d2b_USL&rc=QyEFx8H7XhzPN%2FHl0%2B5m%2FA%3D%3D"/>也相互独立
15、设随机变量X服从两点分布<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa56887_OUL"/>，其分布律为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa59e0e_OUL"/>其中<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa644b2_OUL"/>,则X的特征函数为（）.
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa94e36_USL&rc=QyEFx8H7XhxDxatDFYxEfA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa9b273_USL&rc=QyEFx8H7XhxDxatDFYxEfA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faaa1280_USL&rc=QyEFx8H7XhxDxatDFYxEfA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faaa781b_USL&rc=QyEFx8H7XhxDxatDFYxEfA%3D%3D"/>
16、设随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fa9e43d8_OUL"/>服从参数为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fa9d9d95_OUL"/>的泊松分布，则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fa9e82b2_OUL"/>=（）。
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa1b0bd_USL&rc=QyEFx8H7XhxDxatDFYxEfA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa21926_USL&rc=QyEFx8H7XhxDxatDFYxEfA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa28570_USL&rc=QyEFx8H7XhxDxatDFYxEfA%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143faa2eb8b_USL&rc=QyEFx8H7XhxDxatDFYxEfA%3D%3D"/>
17、设X、Y为相互独立的随机变量，且<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSz5d2ccd3b_143f69aa23e_OUL"/>,<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSz5d2ccd3b_143f69aebad_OUL"/>,则E(X-Y),D(X-Y)分别为（）.
    -1；7
    -1；25
    1；7
    1；25
18、设<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoA55d2ccd3b_143d1d64a0e_OUL"/>服从二维正态分布<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoA55d2ccd3b_143d1d6c5b0_OUL"/>，<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoA55d2ccd3b_143d1d7221b_OUL"/>是<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoA55d2ccd3b_143d1d752fa_OUL"/>独立的（）.
    充分但不必要条件
    必要但不充分条件.
    无关条件
    充分且必要条件
19、下列函数可以作为某个随机变量X的概率密度函数的是（）.
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoA55d2ccd3b_143d1d1b4d5_USL&rc=QyEFx8H7XhxfL6DJhqsA8g%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoA55d2ccd3b_143d1d22c0e_USL&rc=QyEFx8H7XhxfL6DJhqsA8g%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoA55d2ccd3b_143d1d29cad_USL&rc=QyEFx8H7XhxfL6DJhqsA8g%3D%3D"/>
    <imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoA55d2ccd3b_143d1d332f5_USL&rc=QyEFx8H7XhxfL6DJhqsA8g%3D%3D"/>
20、箱中有10个产品，其中2个次品，现从中任取3个产品，用A表示“取到的3个中恰有一个次品”，B表示“取到的3个中没有次品”，C表示“取到的3个都是次品”，D表示“取到的3个中次品数小于3”，则上述四个事件中为基本事件的是（）.
    A
    B
    C
    D
21、X、Y相互独立，则X、Y必不相关.
    A.√
    B.×
22、X～N(3,4),则P(X&lt;3)=P(X&gt;3).
    A.√
    B.×
23、若X～B(3,0.2),Y～B(5,0.2),且X与Y相互独立，则X+Y～B(8,0.2).
    A.√
    B.×
24、每一个连续型随机变量均有方差存在。
    A.√
    B.×
25、设<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_1441473980c_OUL"/>服从<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_14414749791_OUL"/>的均匀分布，<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_1441474de83_OUL"/>，则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSo5d2ccd3b_14462ee1c16_OUL"/>的密度函数为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_144147515a1_OUL"/>。
    A.√
    B.×
26、随机向量（X,Y）服从二元正态分布，则X的边际分布为正态分布，Y的边际分布也为正态分布.
    A.√
    B.×
27、设X服从参数为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_14414708bb9_OUL"/>的泊松分布，则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_1441470c9da_OUL"/>。
    A.√
    B.×
28、已知随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSx5d2ccd3b_1440687c654_OUL"/>的联合分布、边际分布如下表<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSk5d2ccd3b_1445c564bd8_OUL"/>　　则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSx5d2ccd3b_14406888aea_OUL"/>相互独立。
    A.√
    B.×
29、设两个相互独立的随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSx5d2ccd3b_14406857869_OUL"/>，<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSx5d2ccd3b_14406859c71_OUL"/>的方差分别是4和2，则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSx5d2ccd3b_1440685d7e5_OUL"/>＝44。
    A.√
    B.×
30、任意随机变量均存在数学期望。
    A.√
    B.×
31、已知：P(A)=0.2,P(B)=0.5,P(AB)=0.1,则P(A∪B)=0.6.
    A.√
    B.×
32、“A∪B∪C”表示三事件A、B、C至少有一个发生。
    A.√
    B.×
33、特征函数<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSx5d2ccd3b_144067d8ec5_OUL"/>具有性质：<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSx5d2ccd3b_144067dc0b1_OUL"/>。
    A.√
    B.×
34、设X、Y是随机变量，若E(XY)=EX?EY,则X与Y相互独立.
    A.√
    B.×
35、X为随机变量，a,b是不为零的常数，则D(aX+b)=aDX+b.
    A.√
    B.×
36、设<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab96545_OUL"/>为相互独立的随机变量序列，如果数学期望<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab9a0d2_OUL"/>均为有限的，则序列<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab9d8cb_OUL"/>服从大数定律.
    A.√
    B.×
37、设<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab6c6b9_OUL"/>，则<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab7125c_OUL"/>与<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab73677_OUL"/>是相互独立的充分必要条件为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab77961_OUL"/>。
    A.√
    B.×
38、对二项分布<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab08a08_OUL"/>，当<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab0be3b_OUL"/>时，概率值<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSw5d2ccd3b_143fab0f99a_OUL"/>达到最大。
    A.√
    B.×
39、X为随机变量，a,b是不为零的常数，则E(aX+b)=aEX+b.
    A.√
    B.×
40、三事件A、B、C至少有一个发生表示为“A∪B∪C”.
    A.√
    B.×
41、随机变量X服从二项分布b(n,p),当n充分大时，由中心极限定理，X近似服从正态分布N(np,np(1-p)).
    A.√
    B.×
42、n个相互独立的随机变量之积的特征函数等于它们特征函数的乘积。
    A.√
    B.×
43、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504584017310089659.png"title="201709051504584017310089659.png"alt="02641.png"/>
44、设随机变量X的概率密度为且，求<em>k、<em>b的值。
45、
46、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504600676917033398.png"title="201709051504600676917033398.png"alt="02641.png"/>
47、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504584286190056909.png"title="201709051504584286190056909.png"alt="02641.png"/>
48、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504584839529043095.png"title="201709051504584839529043095.png"alt="02641.png"/>
49、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504603416730005341.png"title="201709051504603416730005341.png"alt="02641.png"/>
50、设随机事件A的概率为P(A)=0.5,随机事件B的概率为P(B)=0.4，条件概率：由乘法公式<imgtitle="201609131473752407527058258.png"alt="image.png"src="http://zuoye.eduwest.com/resourcefile/uploadFiles/file/questionImgs/201609131473752407527058258.png"/><imgtitle="201609131473752421449010759.png"alt="image.png"src="http://zuoye.eduwest.com/resourcefile/uploadFiles/file/questionImgs/201609131473752421449010759.png"/>
51、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504596655360035243.png"title="201709051504596655360035243.png"alt="02641.png"/>
52、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504584598388065564.png"title="201709051504584598388065564.png"alt="02641.png"/>
53、设二维随机变量<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSz5d2ccd3b_143f6d1b17a_OUL"/>的联合密度函数为<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSz5d2ccd3b_143f6d1fee6_OUL"/>求：（1）常数<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSz5d2ccd3b_143f6d294c8_OUL"/>；（2）概率<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSz5d2ccd3b_143f6d2f9cd_OUL"/>；（3）X的边际密度函数<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSz5d2ccd3b_143f6d342ba_OUL"/>。
54、<imgtitle="201609131473750667533049542.png"alt="image.png"src="http://zuoye.eduwest.com/resourcefile/uploadFiles/file/questionImgs/201609131473750667533049542.png"/>，<imgtitle="201609131473750696442021928.png"alt="image.png"src="http://zuoye.eduwest.com/resourcefile/uploadFiles/file/questionImgs/201609131473750696442021928.png"/>，求<imgtitle="201609131473750624299093527.png"alt="image.png"src="http://zuoye.eduwest.com/resourcefile/uploadFiles/file/questionImgs/201609131473750624299093527.png"/>。
55、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504601127202042754.png"title="201709051504601127202042754.png"alt="02641.png"/>
56、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504584983839098388.png"title="201709051504584983839098388.png"alt="02641.png"/>
57、某机器生产的螺栓长度<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_14414b6f82e_OUL"/>（单位：cm）服从正态分布<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_14414b73766_OUL"/>，规定长度在范围<imgsrc="http://fs.eduwest.com/filesys/image.jsp?fc=00quoSc5d2ccd3b_14414b79a9d_OUL"/>内为合格，求一螺栓不合格的概率。
58、已知产品中96％是合格品，现有一种简化的检验方法，它把真正的合格品确认为合格品的概率为0.98，而误认废品为合格品的概率为0.05，求：(1)产品以简化法检验为合格品的概率；（2）以简化方法检验为合格品的一个产品确实为合格品的概率。
59、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504601510492032887.png"title="201709051504601510492032887.png"alt="02641.png"/>
60、<imgsrc="/resourcefile/uploadFiles/file/questionImgs/201709051504585242916004420.png"title="201709051504585242916004420.png"alt="02641.png"/>
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