![](https://img.xkw.com/dksih/QBM/2015/10/8/1572248643444736/1572248649457664/STEM/0ec97637ea4549e490875bd3862eb1de.png)
![](https://img.xkw.com/dksih/QBM/2015/10/8/1572248643444736/1572248649457664/STEM/ca18dd426e024a288b38022b1b435682.png)
![](https://img.xkw.com/dksih/QBM/2015/10/8/1572248643444736/1572248649457664/STEM/38e1b7dad8054cb982a0c4f561bd7a03.png)
![](https://img.xkw.com/dksih/QBM/2015/10/8/1572248643444736/1572248649457664/STEM/eb89b4bf98cf41098c8a601a0b49fcb1.png)
(1)求第四小组的频率,补全这个频率分布直方图;并估计该校学生的数学成绩的中位数.
(2)从数学成绩是70分以上(包括70分)的学生中选两人,求他们在同一分数段的概率.
(3)若从全市参加高一年级期末考试的学生中,任意抽取4个学生,设这四个学生中数学成绩为80分以上(包括80分)的人数为X,(以该校学生的成绩的频率估计概率),求X的数学期望.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f8c2a91a15e1f7b296b64d3bd2e7551.png)
![](https://img.xkw.com/dksih/QBM/2019/11/20/2338047817670656/2338465186267136/STEM/37b3600f-5b8f-4a1b-8e19-cd6fb8af60d8.png?resizew=323)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
(2)填写下表,能否有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02ca40b5a7476f844dad0e5f79fa69aa.png)
男生 | 女生 | 总计 | |
成绩不高于平均数 | |||
成绩高于平均数 | |||
总计 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e3821f70c08c5180e9b3086d3c9610f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/356b05e46b10ee51c3e43546d73ec96c.png)
![]() | 0.05 | 0.01 | 0.005 | 0.001 |
![]() | 3.841 | 6.635 | 7.879 | 10.828 |
函数 | 使函数有意义的x的实数范围 | |
1 | ||
2 | ||
3 | ||
4 | ||
5 | ||
6 |
分数![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
人数 | 20 | 55 | 105 | 70 | 50 |
参加自主招生获得通过的概率 | 0.9 | 0.8 | 0.6 | 0.5 | 0.4 |
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/491c4587-02e0-4a1d-9f59-33dd705984e7.png?resizew=310)
优等生 | 非优等生 | 总计 | |
学习大学先修课程 | |||
没有学习大学先修课程 | |||
总计 |
①在今年参与大学先修课程的学生中任取一人,求他获得某高校自主招生通过的概率;
②设今年全校参加大学先修课程的学生获得某高校自主招生通过的人数为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33470bee4febd946d39f7b63d6344c8f.png)
参考数据:
![]() | 0.15 | 0.10 | 0.05 | 0.025 | 0.010 | 0.005 |
![]() | 2.072 | 2.706 | 3.841 | 5.024 | 6.635 | 7.879 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bc485c58dbd6e50bfb352030f4a1c42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/356b05e46b10ee51c3e43546d73ec96c.png)
5 . 教育是阻断贫困代际传递的根本之策.补齐贫困地区义务教育发展的短板,让贫困家庭子女都能接受公平而有质量的教育,是夯实脱贫攻坚根基之所在.治贫先治愚,扶贫先扶智.为了解决某贫困地区教师资源匮乏的问题,某市教育局拟从5名优秀教师中抽选人员分批次参与支教活动.支教活动共分3批次进行,每次支教需要同时派送2名教师,且每次派送人员均从这5人中随机抽选.已知这5名优秀教师中,2人有支教经验,3人没有支教经验.
(1)求5名优秀教师中的“甲”,在这3批次支教活动中恰有两次被抽选到的概率;
(2)求第一次抽取到无支教经验的教师人数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7def23f30138e0b7c4c1e498d6903a6c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a8ec38ab7e6912bcc97513a359bd5e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1320e2e9d9c398ec700482b06153d05b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e82778985cd2e9f80ca7b7cabb1a85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9632e7e5a6eb0c85cb44940c60618d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57483e04fd1840c87ac5325157149877.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d46e92ff41a3037a51bf594df6f73bc3.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9169c81b9643e9dcd5c945d580186c97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e06ae105393888c9e02fb2437428217c.png)
(4)数列求和问题的关键是根据通项公式特点找到适合的求和方法,并进行合理变形,观察下列数列通项公式特点,填表:
通项公式 | 求和方法名称 | 变形成可求和形式 |
![]() | ||
![]() | ||
![]() |
分数 | |||||
人数 | 20 | 55 | 105 | 70 | 50 |
参加自主招生获得通过的概率 | 0.9 | 0.8 | 0.6 | 0.5 | 0.4 |
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/7/0386d3a0-02e8-4b52-9439-0af33b81bab1.png?resizew=214)
优等生 | 非优等生 | 总计 | |
学习大学先修课程 | |||
没有学习大学先修课程 | |||
总计 |
①在今年参与大学先修课程的学生中任取一人,求他获得某高校自主招生通过的概率;
②某班有4名学生参加了大学先修课程的学习,设获得某高校自主招生通过的人数为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
参考数据:
0.15 | 0.10 | 0.05 | 0.025 | 0.010 | 0.005 | |
2.072 | 2.706 | 3.841 | 5.024 | 6.635 | 7.879 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72a816fb48423a40ae581ad383676a74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61dfb43eae40a12e896ac96dc14a4103.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/356b05e46b10ee51c3e43546d73ec96c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e6486784415f3537c9a13556c05d893.png)
(1)求甲、乙两人投票方案不同的概率;
(2)若某人选择方案A或方案B,则对应方案可获得2票,选择方案C,则方案C获得1票,设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://img.xkw.com/dksih/QBM/2017/3/19/1647003663228928/1649338964672512/STEM/736865ca924c4ee6acb2ede89fcd83f6.png?resizew=358)
(Ⅰ)根据频率分布直方图填写下面2×2列联表;
甲班(A方式) | 乙班(B方式) | 总计 | |
成绩优秀 | |||
成绩不优秀 | |||
总计 |
(Ⅱ)判断能否在犯错误的概率不超过0.05的前提下认为:“成绩优秀”与教学方式有关?
附:.
P(K2≥k) | 0.25 | 0.15 | 0.10 | 0.05 | 0.025 |
k | 1.323 | 2.072 | 2.706 | 3.841 | 5.024 |
(1)求5名优秀教师中的“甲”,在这3批次支教活动中恰有两次被抽选到的概率;
(2)求第一次抽取到无支教经验的教师人数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
(3)求第二次抽选时,选到没有支教经验的教师的人数最有可能是几人?请说明理由.