名校
解题方法
1 . 若
,
是样本空间
上的两个离散型随机变量,则称
是
上的二维离散型随机变量或二维随机向量.设
的一切可能取值为
,
,记
表示
在
中出现的概率,其中
.
(1)将三个相同的小球等可能地放入编号为1,2,3的三个盒子中,记1号盒子中的小球个数为
,2号盒子中的小球个数为
,则
是一个二维随机变量.
①写出该二维离散型随机变量
的所有可能取值;
②若
是①中的值,求
(结果用
,
表示);
(2)
称为二维离散型随机变量
关于
的边缘分布律或边际分布律,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5c1116ce7f5a1a7b57517276d5092fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fadab9bb02100d7e9f12989b89721482.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66ae8920473eb5e860b0d625d0fe07eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8038ba89dea0aa5c0e760bb5ed5f8561.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fadab9bb02100d7e9f12989b89721482.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cffa35373ec4e4684107b42adb7a5161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00e2fc8dcdb957351e81bd926db46ef9.png)
(1)将三个相同的小球等可能地放入编号为1,2,3的三个盒子中,记1号盒子中的小球个数为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5c1116ce7f5a1a7b57517276d5092fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
①写出该二维离散型随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a64d924836b4292239d9726c6473d7f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a061d6375056092d2d831bd7cae6988.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fbefad0c67ac64be204e45c95b2dc35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4d15d2e2dc5b64da00f2f90613f6b73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbe4cecc21cb09b200a771b8ec5cea0f.png)
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2024-03-29更新
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4卷引用:2024届山东省滨州市一模联考数学试题