连续型随机变量的分布函数为，，则的分布密度函数为( )。55a0b189e4b04cd76d4aa7bb.gifafe48a3281e1b67421324cdcfb89c0ff.gif5597fae3e4b0ec35e2d5b5b6.gif55a0b189e4b04cd76d4aa7bb.gif

A .https://assets.asklib.com/images/image2/2017051115162944615.png B .https://assets.asklib.com/images/image2/2017051115164423200.png C .https://assets.asklib.com/images/image2/2017051115165539302.png D .https://assets.asklib.com/images/image2/201705111517072299.png

A .https://assets.asklib.com/images/image2/2017051115131931198.png B .https://assets.asklib.com/images/image2/201705111513261131.png C .https://assets.asklib.com/images/image2/2017051115133213568.png D .https://assets.asklib.com/images/image2/2017051115133961141.png

A . 正确 B . 错误

A、A=1 B=0 B、A=B=0.5 C、A=0 B=1 D、A=0.5，B=<img src="/ananas/latex/p/24775">

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设连续型随机变量X的分布函数为<img src='https://img2.soutiyun.com/ask/2020-10-30/972912565646551.png' /> 求系数A, P(0.3＜X ＜0.7),概率密度f(x)。

A.<img src='https://img2.soutiyun.com/ask/2020-10-04/970660847536956.png' /> B.<img src='https://img2.soutiyun.com/ask/2020-10-04/970660856247455.png' /> C.F(a) D.2F(a)-1

二维连续型随机向量(X，Y)的联合概率密度为<img src='https://img2.soutiyun.com/ask/2020-12-31/978284874696433.jpg' /> 试确定A的值并求(X，Y)的联合分布函数。

A．P(X＞b)=1-F(b) B．P(X=a)=0 C．<img src='https://img2.soutiyun.com/ask/uploadfile/6663001-6666000/4542cc99e5c66e758cc6e88d9f65e164.png' />D．<img src='https://img2.soutiyun.com/ask/uploadfile/6663001-6666000/60caca0148aa7397cd929e9d3025f1d9.png' />

设连续型随机变量ξ的密度函数为<img src='https://img2.soutiyun.com/ask/2020-08-04/965403848617315.png' />P(1＜ξ＜3)=0.25,求(1)常数a,b;(2)ξ的分布函数;(3)P(ξ＞1.5).

某随机变量X服从均匀分布，其密度函数为f(x)=-0.5。()

设随机变量X的分布函数为<img src='https://img2.soutiyun.com/ask/2020-07-31/965043767406134.png' /> 若P{X=3}=0.1，求常数C.这时X是连续型随机变量吗？说明理由.

设随机变量X的密度函数为φ(x)，且φ(－x)＝φ(x)，F(x)为X的分布函数，则对任意实数a，有()． <img src='https://img2.soutiyun.com/ask/uploadfile/2160001-2163000/4fc3fa773ba3ff1b4a790c7f86a536e7.jpg' />

设连续随机变量X的密度函数p(x)是一个偶函数，F(x)为X的分布函数，求证对任意实数a＞0，有 <img src='https://img2.soutiyun.com/ask/2020-08-03/965297607418991.png' />

设随机变量X的密度函数为<img src='https://img2.soutiyun.com/ask/2020-09-29/970257357637827.png' />，试利用正态分布的密度函数性质求未知参数A的数值。

设随机变量X的分布函数为F(x)。则<img src='https://img2.soutiyun.com/ask/2020-07-24/964431375767443.png' />的分布函数G(y)为()。 A.<img src='https://img2.soutiyun.com/ask/2020-07-24/964431401000886.png' /> B.<img src='https://img2.soutiyun.com/ask/2020-07-24/964431408783331.png' /> C.<img src='https://img2.soutiyun.com/ask/2020-07-24/964431418271873.png' /> D.<img src='https://img2.soutiyun.com/ask/2020-07-24/964431425318276.png' />

设随机变量X的分布密度函数为<img src='https://img2.soutiyun.com/ask/2020-08-05/965469476347499.png' /> 求E(X)及D(X)。