解题方法
1 . 为了加强环保知识的宣传,某学校组织了垃圾分类知识竞赛活动.活动设置了四个箱子,分别写有“厨余垃圾”、“有害垃圾”、“可回收物”、“其它垃圾”;另有卡片若干张,每张卡片上写有一种垃圾的名称.每位参赛选手从所有卡片中随机抽取
张,按照自己的判断将每张卡片放入对应的箱子中.按规则,每正确投放一张卡片得
分,投放错误得
分.比如将写有“废电池”的卡片放入写有“有害垃圾”的箱子,得
分,放入其它箱子,得
分.从所有参赛选手中随机抽取
人,将他们的得分按照
、
、
、
、
分组,绘成频率分布直方图如图:
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/817abdb4-50ba-4814-b1ce-a8c9940fb79a.png?resizew=257)
(1)分别求出所抽取的
人中得分落在组
和
内的人数;
(2)从所抽取的
人中得分落在组
的选手中随机选取
名选手,以
表示这
名选手中得分不超过
分的人数,求
的分布列和数学期望.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b7f27ebcef70a3ebbbe8d2e53ea0896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c95b6be4554f03bf496092f1acdfbb89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c95b6be4554f03bf496092f1acdfbb89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b7f27ebcef70a3ebbbe8d2e53ea0896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1884b0525f15220a3aa966f75928daca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f1416bbe317c1c68814473a92e55d90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b56b3c89f74bf88b956cd1743af755c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1a56a1e37424d9f3fd7ccdc52388ef4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c578cc1e837a081232b45d75c4cb8ef2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/817abdb4-50ba-4814-b1ce-a8c9940fb79a.png?resizew=257)
(1)分别求出所抽取的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b7f27ebcef70a3ebbbe8d2e53ea0896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1884b0525f15220a3aa966f75928daca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f1416bbe317c1c68814473a92e55d90.png)
(2)从所抽取的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b7f27ebcef70a3ebbbe8d2e53ea0896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5f3276205486c639046bd6acf2dbea5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b7f27ebcef70a3ebbbe8d2e53ea0896.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
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2020-04-14更新
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3卷引用:2020届四川省宜宾市高三第二次诊断测试理科数学试题