连续掷一枚质地均匀的骰子3次,各次互不影响,记
为出现6点的次数,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e60ff3d4d0abd4a75cc521c0267f92e.png)
A.![]() | B.![]() | C.![]() | D.![]() |
更新时间:2020-06-11 20:20:43
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解题方法
【推荐1】下列正确命题的序号有( )
①若随机变量
,且
,则
.
②在一次随机试验中,彼此互斥的事件
,
,
,
的概率分别为
,
,
,
,则
与
是互斥事件,也是对立事件.
③一只袋内装有
个白球,
个黑球,连续不放回地从袋中取球,直到取出黑球为止,设此时取出了
个白球,
.
④由一组样本数据
,
,…
得到回归直线方程
,那么直线
至少经过
,
,…
中的一个点.
①若随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15fa906772a8a407cb831dadb9a5ec72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/968a7dfbca438c54c380aa4318310289.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/933e3a8f932a3f3eec88ae81af74b74a.png)
②在一次随机试验中,彼此互斥的事件
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4646418552dc060ebda1232361a01295.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4646418552dc060ebda1232361a01295.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7412fd1be21e4eaf388963a82ac2b11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7412fd1be21e4eaf388963a82ac2b11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b07c52d92501c4589eeedbb64d5fba91.png)
③一只袋内装有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64da75a02173c2a5eb40f4c68d0f4f36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80c68f3d33296128f4cca19d6986e61b.png)
④由一组样本数据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56720e2f2b0ddd72156da495923698da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2852ae85cfcc804b3192ea8543c88938.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92abae836b8026511113ad8c3ea23028.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33b447ac3d1a965572c31b6e4c18d4b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33b447ac3d1a965572c31b6e4c18d4b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56720e2f2b0ddd72156da495923698da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2852ae85cfcc804b3192ea8543c88938.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92abae836b8026511113ad8c3ea23028.png)
A.②③ | B.①② | C.③④ | D.①④ |
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【推荐2】某人从家乘车到单位,途中经过3个路口.假设在各路口遇到红灯的事件是相互独立的,且概率都是0.4,则此人上班途中遇到红灯的次数的方差为( )
A.0.48 | B.1.2 |
C.0.72 | D.0.6 |
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【推荐3】已知随机变量X,Y满足
,且
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d70012f3c462d4911bf6cbdc0e6b119.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48593999072abe3c48509ea018f77e3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/626ccf5514f7272d78cc964e8f87a21b.png)
A.2.4 | B.3.4 | C.4.2 | D.4.4 |
您最近一年使用:0次