已知随机变量ξ的分布列为:
若
,则a+b=______ ,D(
)=______ .
![]() | ﹣1 | 0 | 1 | 2 |
P | ﹣2a | ![]() | ![]() | b |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fbdd06acf22f297438e6e21aeb391da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
20-21高二·全国·单元测试 查看更多[2]
(已下线)第七章 随机变量及其分布(基础卷)-《阳光测评》2020-2021学年高二数学单元提升卷(人教A版2019选择性必修第三册)浙江省金华第一中学2020-2021学年高三上学期10月月考数学试题
更新时间:2021-10-05 19:56:57
|
相似题推荐
填空题-单空题
|
较易
(0.85)
【推荐1】有甲、乙两种品牌的手表,它们的日走时误差分别为
(单位:
),其分布如下:
则两种品牌中质量好的是____________.(填甲或乙)
![](https://img.xkw.com/dksih/QBM/2011/9/2/1570300047056896/1570300052045824/STEM/01a191f7aceb440bba1c2e8a67b5771f.png?resizew=43)
![](https://img.xkw.com/dksih/QBM/2011/9/2/1570300047056896/1570300052045824/STEM/5b22cb2512454320a9bd2c4d6737aa4b.png?resizew=12)
![]() | ![]() | 0 | 1 |
![]() | 0.1 | 0.8 | 0.1 |
![]() | ![]() | ![]() | 0 | 1 | 2 |
![]() | 0.1 | 0.2 | 0.4 | 0.2 | 0.1 |
您最近一年使用:0次
填空题-双空题
|
较易
(0.85)
【推荐2】在一个口袋中装有4个白球和2个黑球,这些球除颜色外完全相同.甲、乙两人先后从袋中各随机摸出1球,不放回,记为1次摸球,直到有人摸出黑球为止.设摸球的次数为
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a1d17e01b5ac2c39647c48e3124f685.png)
___________ ,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc23dc1709498e8920d7d243213190b2.png)
___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a1d17e01b5ac2c39647c48e3124f685.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc23dc1709498e8920d7d243213190b2.png)
您最近一年使用:0次
填空题-单空题
|
较易
(0.85)
名校
解题方法
【推荐1】设随机变量
可能的取值为1,2,3,4,
,又
的数学期望为
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fb2f87452a6a5fe9dd73766b16d66bf.png)
_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef8331019abb141f862ee3f64d237849.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a834ba133848ef3bc0f9b1b2466caa64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fb2f87452a6a5fe9dd73766b16d66bf.png)
您最近一年使用:0次
填空题-单空题
|
较易
(0.85)
【推荐2】已知某一随机变量
的概率分布列如表所示,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc23dc1709498e8920d7d243213190b2.png)
_____ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a834ba133848ef3bc0f9b1b2466caa64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc23dc1709498e8920d7d243213190b2.png)
X | a | 3 | 4 |
P | 0.1 | 0.7 | b |
您最近一年使用:0次