1 .
年
月
日,国家主席习近平在第七十五届联合国大会一般性辩论上发表重要讲话,指出要加快形成绿色发展方式和生活方式,建设生态文明和美丽地球.中国将提高国家自主贡献力度,采取更加有力的政策和措施,二氧化碳排放力争于
年前达到峰值,努力争取
年前实现碳中和.某企业为了响应中央号召,准备在企业周边区域内通过植树造林实现减碳,从某育苗基地随机采购了
株银杏树树苗进行栽种,测量树苗的高度,得到如下频率分布直方图,已知不同高度区间内树苗的售价区间如下表.
![](https://img.xkw.com/dksih/QBM/2021/5/10/2718243723403264/2719442358771712/STEM/bd6b6862-70a7-4f34-99db-206a7345fc7c.png?resizew=341)
(1)现从
株树苗中,按售价分层抽样抽取
株,再从中任选三株,求售价之和高于
元的概率;
(2)已知该育苗基地银杏树树苗高度服从正态分布
,并用该企业采购的
株树苗作样本,来估计总体期望和方差(同一组中的数据用该组区间的中点值作代表),且
.
①若该育苗基地共有
株银杏树树苗,并将树苗的高度从高到低进行排列,得到数列
,求
的估计值.
②若从该育苗基地银杏树树苗中任选
株,记树苗高度超过
的株数为
,求随机变量
的分布列和期望.
参考数据:若
,
,
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/701554763bdbbf2689a8dae07608da38.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8d02ea8c4988c5c28ab93f0d70fb55a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f76fba0fe83cf0aa9a68210591cac1a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf9123c858a96fd6a2e5ecf7581e6de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f9afa0d8a40d5938ce7ad754da6fff1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfd121f4aeca8a78a320fca1fd1c4d07.png)
树苗高度( | |||
树苗售价(元/株) |
![](https://img.xkw.com/dksih/QBM/2021/5/10/2718243723403264/2719442358771712/STEM/bd6b6862-70a7-4f34-99db-206a7345fc7c.png?resizew=341)
(1)现从
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfd121f4aeca8a78a320fca1fd1c4d07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3304e23f3b0f9569c4140ca89b6498.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c748e40ba21ac5063d3bccaa57ef278.png)
(2)已知该育苗基地银杏树树苗高度服从正态分布
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29bcc248a7770a16fa10fc4602d71e0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfd121f4aeca8a78a320fca1fd1c4d07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1eb3e370c54f5bf870deb3ffb69b6125.png)
①若该育苗基地共有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d4b31ff8c25710c8c0d3480f5c18d3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6942a724c3e02242de57dc8c364e21a3.png)
②若从该育苗基地银杏树树苗中任选
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b6c88768e159c0d5b45c7e5b9774e31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
参考数据:若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1290917c2c835b61384480b335cc1d13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3118f3aff3ef82c26642250c5d5d97a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5d13dc05439f35f2d0c8644c3ac4f5d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4acb398b0afedf2963ac1d68cea4850d.png)
您最近一年使用:0次
2021-05-12更新
|
1309次组卷
|
5卷引用:江西省九江市2021届高三三模数学(理)试题
解题方法
2 . 疫情防控期间,为了让大家有良好的卫生习惯某校组织了健康防护的知识测试(百分制)活动,活动结束后随机抽取了
名学生的成绩,并计算得知这
个学生的平均成绩为
,其中
个低分成绩分别是
、
、
、
、
;而产生的
个高分成绩分别是
、
、
、
、
、
、
、
、
、
.
(1)为了评估该校的防控是否有效,以样本估计总体,将频率视为概率,若该校学生的测试得分近似满足正态分布
(
和
分别为样本平均数和方差),则认为防控有效,否则视为效果不佳.经过计算得知样本方差为
,请判断该校的疫情防控是否有效,并说明理由.(参考数据:
)规定:若
,
,则称变量
“近似满足正态分布
的概率分布”.
(2)学校为了鼓励学生对疫情防控的配合,决定对
分及以上的同学通过抽奖的方式进行奖励,得分低于
分的同学只有一次抽奖机会,不低于
分的同学有两次抽奖机会.每次抽奖获得
元奖金的概率是
,获得
元的概率是
.现在从这
个高分学生中随机选一名,记其获奖金额为
,求
的分布列和数学期望.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90dd550e1ad9bbf01687ffb4aab788ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90dd550e1ad9bbf01687ffb4aab788ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f64730802070a68d4f854b332a24814.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b53c7539ed297ea63b9ace6f5cc58ca8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ec714b7d7a203ecbcef9232ee7d40da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba505969331b28f0e2d3047d49988914.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26a49a952a95f7af7d8b4bc55f0fbe03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26a49a952a95f7af7d8b4bc55f0fbe03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07ae0b4264da6a8812454ffd2f20d94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a17161b28b6ad8f57abc5b11e1b6c671.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6d314c287aa376240f0ca41bd181f01.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6d314c287aa376240f0ca41bd181f01.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d0c86435b0b5f7dabce768a0790c346.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d0c86435b0b5f7dabce768a0790c346.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e4c1474b253f01cb4766a9e742b9dc2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/128de649220637bdc96fc3e508592201.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c804623afb11ea99366d6a50043ccb78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
(1)为了评估该校的防控是否有效,以样本估计总体,将频率视为概率,若该校学生的测试得分近似满足正态分布
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29bcc248a7770a16fa10fc4602d71e0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1100379a4385b9ce064847bc21760adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/742d3e642d52e01899f66df411100838.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b88b4213192069c5c22e7c97f6242c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2c06929d5ac5b6eb7722181239de779.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2341e6f3e98d46aa511abe1e48a8f597.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40ad392e94459218936b0681adfd4734.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29bcc248a7770a16fa10fc4602d71e0e.png)
(2)学校为了鼓励学生对疫情防控的配合,决定对
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a17161b28b6ad8f57abc5b11e1b6c671.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0538cad6b26c7238b90e664bb68c27c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0538cad6b26c7238b90e664bb68c27c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e6f1af4b44b2e97e8f319bab4ae9010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b2a698891d42c70b597f0da4f215f09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d266a04f3dc7483eddbc26c5e487db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07ae0b4264da6a8812454ffd2f20d94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a829fdd8ec0f3b7ede883cf2c3e53b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a829fdd8ec0f3b7ede883cf2c3e53b.png)
您最近一年使用:0次
2021-02-04更新
|
1180次组卷
|
4卷引用:江西省鹰潭市2021届高三高考二模数学(理)试题
名校
3 . 2019年6月25日,《固体废物污染环境防治法(修订草案)》初次提请全国人大常委会审议,草案对“生活垃圾污染环境的防治”进行了专章规定.草案提出,国家推行生活垃圾分类制度.为了了解人民群众对垃圾分类的认识,某市环保部门对该市市民进行了一次垃圾分类网络知识问卷调查,每一位市民仅有一次参加机会,通过随机抽样,得到参加问卷调查的1000人(其中450人为女性)的得分(满分:100分)数据,统计结果如表所示:
(1)由频数分布表可以认为,此次问卷调查的得分
服从正态分布
,
近似为这1000人得分的平均值(同一组数据用该组区间的中点值作为代表),请利用正态分布的知识求
;
(2)把市民分为对垃圾分类“比较了解”(不低于60分的)和“不太了解”(低于60分的)两类,请完成如下
列联表,并判断是否有
的把握认为市民对垃圾分类的了解程度与性别有关?
(3)从得分不低于
分的被调查者中采用分层抽样的方法抽取
名.再从这
人中随机抽取
人,求抽取的
人中男性人数的分布列及数学期望.
参考数据:①
;②若
,则
,
,
;
③
,
得分 | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
男性人数 | 15 | 90 | 130 | 100 | 125 | 60 | 30 |
女性人数 | 10 | 60 | 70 | 150 | 100 | 40 | 20 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8b9ad2fcfff3dd546c5fdbedfe6238.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff3862a39c00bbc44b2703e1d3556463.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1100379a4385b9ce064847bc21760adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b10afc68c2d802a382bbc079a3f7d5fe.png)
(2)把市民分为对垃圾分类“比较了解”(不低于60分的)和“不太了解”(低于60分的)两类,请完成如下
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b72fcdc709e77910cd36a26369648b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95c487ba8259608d3cb24fb594ffbd7b.png)
不太了解 | 比较了解 | 合计 | |
男性 | |||
女性 | |||
合计 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1f959e5f8d89390f0f136f6acc9f6fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07ae0b4264da6a8812454ffd2f20d94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07ae0b4264da6a8812454ffd2f20d94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
参考数据:①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2c06929d5ac5b6eb7722181239de779.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53c1ed67167078ea4f5f1ee53ee14164.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a73c92c442a142d4e5fc618dc00bcf30.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b65e903fb7fe549c73f55779df19729f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/112b77b25edccc41e2253c5b779d107e.png)
③
![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e3821f70c08c5180e9b3086d3c9610f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ed61b3bc78fdb0a01f901c6f081c089.png)
您最近一年使用:0次
2020-12-10更新
|
1104次组卷
|
4卷引用:江西省新余市第一中学2020-2021学年高二年级第六次考试数学(理)试题
江西省新余市第一中学2020-2021学年高二年级第六次考试数学(理)试题(已下线)8.3 分类变量与列联表(精练)-2020-2021学年高二数学一隅三反系列(人教A版2019选择性必修第三册)山东省高考联盟2020-2021学年高三下学期开学收心考试数学试题山东省济南莱州市2020-2021学年高三上学期开学考试数学试题