![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7de0205dcad1b1190fb905dfdb7b972.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
2 . 某纺织厂为了生产一种高端布料,准备从A农场购进一批优质棉花,厂方技术员从A农场存储的优质棉花中随机抽取了100处棉花,分别测量了其纤维长度(单位:mm)的均值,收集到100个样本数据,并制成如下频数分布表:
长度(单位:mm) | [23,25) | [25,27) | [27,29) | [29,31) | [31,33) | [33,35) | [35,37) | [37,39] |
频数 | 4 | 9 | 16 | 24 | 18 | 14 | 10 | 5 |
(1)求这100个样本数据的平均数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c85481cd7e94130ef3aa05b4a39e79cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/671f43c79d612c93a6d160335e86e177.png)
(2)将收集到的数据绘成直方图可以认为这批棉花的纤维长度服从分布
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1290917c2c835b61384480b335cc1d13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/594f4ea0d5f4a741355161af9eb34104.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48d1316cf501a47b6d75594091d5f4a4.png)
①利用正态分布,求;
②纺织厂将A农场送来的这批优质棉进行二次检验,从中随机抽取20处测量其纤维均值yi(i=1,2…,20),数据如下:
y1 | y2 | y3 | y4 | y5 | y6 | y7 | y8 | y9 | y10 |
24.1 | 31.8 | 32.7 | 28.2 | 28.4 | 34.3 | 29.1 | 34.8 | 37.2 | 30.8 |
y11 | y12 | y13 | y14 | y15 | y16 | y17 | y18 | y19 | y20 |
30.6 | 25.2 | 32.9 | 27.1 | 35.9 | 28.9 | 33.9 | 29.5 | 35.0 | 29.9 |
若20个样本中纤维均值的频率不低于①中
即可判断该批优质棉花合格,否则认为农场运送时掺杂了次品,判断该批棉花不合格.按照此依据判断A农场送来的这批棉花是否为合格的优质棉花,并说明理由.
附:若,则
,
,
月份x | 1 | 2 | 3 | 4 | 5 | 6 |
收入y(百万元) | 6.6 | 8.6 | 16.1 | 21.6 | 33.0 | 41.0 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e136e7637543c8ae92c8dcd55b31924.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dce47dc395ec0d16badd23034fb29bd7.png)
(2)根据(1)的结果及表中的数据,求出y关于x的回归方程,并预测该公司7月份的5G经济收入.(结果保留小数点后两位)
(3)从前6个月的收入中抽取2个,记收入超过20百万元的个数为X,求X的分布列和数学期望.参考数据:
![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
3.50 | 21.15 | 2.85 | 17.70 | 125.35 | 6.73 | 4.57 | 14.30 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97b4b9113c0ea3ff72ee8ecebeaf68cf.png)
参考公式:对于一组具有线性相关关系的数据(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97ea8f47d8d8d9e1832d52b1c7425450.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be3069959e6676e603dfa3494c66e6df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11f4b0349a18ff53b0dc748374c24ae4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/763dd2f72fbe6fedfcabf3d0b19d625c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbe46155395f53ee859fdd469939a64a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
月份![]() | 1 | 2 | 3 | 4 | 5 | 6 |
收入![]() | 6.8 | 8.6 | 16.1 | 19.6 | 28.1 | 40.0 |
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/8/f04e0350-445c-4b8b-90d3-9d4ba8c56353.png?resizew=172)
(1)根据散点图判断,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e136e7637543c8ae92c8dcd55b31924.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/581a6a69f1039aa12764eea5bf7ef405.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(2)根据(1)的结果及表中的数据,求出y关于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(3)该车企为提高新能源汽车的安全性,近期配合中国汽车技术研究中心进行了包括跌落、追尾、多车碰撞等一系列安全试验项目,其中在实验场进行了一项甲、乙、丙三车同时去碰撞实验车的多车碰撞实验,测得实验车报废的概率为0.188,并且当只有一车碰撞实验车发生,实验车报废的概率为0.1,当有两车碰撞实验车发生,实验车报废的概率为0.2,由于各种因素,实验中甲乙丙三车碰撞实验车发生概率分别为0.7,0.5,0.4,且互不影响,求当三车同时碰撞实验车发生时实验车报废的概率.
参考数据:
![]() | ![]() | ![]() | ![]() | ![]() |
19.87 | 2.80 | 17.50 | 113.75 | 6.30 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c9607020fd3480f5cc027909a0a27fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c5fd3eff2d3f8fd3c1e2a8c6b6a87e6.png)
参考公式:对于一组具有线性相关关系的数据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fc6c2985104b07933ffc17c2e5aab3b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baab719e8fe66a8866e8971e426302dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/238a8f3ee9f23642c22142b117404570.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b68acb9c8296e0dbf1ee49ab1768742.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97ea8f47d8d8d9e1832d52b1c7425450.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c89e6ea6c7659f973509b287fb841285.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/11/8e00abac-ff66-49f4-b308-e6d95a7cdfc5.png?resizew=321)
(1)利用散点图判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6a5b1c19e4c57f1d259f8269e551c64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba7c4f1ac6cc57f6c5084479badd1f71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca31577dd76afbc1b720cdcad88ffd16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
(2)对数据作出如下处理,令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6363919698a207f13390fa7405c85cc7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![]() | ![]() | ![]() | ![]() |
15 | 15 | 28.25 | 56.5 |
附:对于一组数据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ee2df58159c47a69be9e3f9cfe8c2a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0940cc781cd9cb5c05a3795acec775cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c5a0bfe22905260f047609a4180c21e.png)
6 . 为了研究某种细菌随天数x变化的繁殖个数y,收集数据如下:
天数x | 1 | 2 | 3 | 4 | 5 | 6 |
繁殖个数y | 6 | 12 | 25 | 49 | 95 | 190 |
(1)在图中作出繁殖个数y关于天数x变化的散点图,并由散点图判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33b447ac3d1a965572c31b6e4c18d4b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b96969c5c96977de135616a637ddc52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7936359df4c926b72b48c6fdae55f12d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b76f79be89b8c6227b68eded6b675546.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ec26e45ae36c71ee9761a05e734dde1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b707f7a60da910e1dae29c79dff3300.png)
(2)对于非线性回归方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b96969c5c96977de135616a637ddc52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7936359df4c926b72b48c6fdae55f12d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b76f79be89b8c6227b68eded6b675546.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ec26e45ae36c71ee9761a05e734dde1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b707f7a60da910e1dae29c79dff3300.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54d28162b2a8309f0f7f193e733be414.png)
3.50 | 62.83 | 3.53 | 17.50 | 596.57 | 12.09 |
①证明:“对于,令
,可以得到繁殖个数的对数z关于天数x具有
,β,α为常数)”;
②根据(1)的判断结果及表中数据,建立y关于x的回归方程(系数保留2位小数).
附:对于一组数据,
,…,
,其回归直线方程
的斜率和截距的最小二乘估计分别为
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![]() | ![]() | ![]() |
![]() | ![]() | ![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d97a1454ac85ee201055d8e55cedef48.png)
(1)根据散点图判断两变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6a5b1c19e4c57f1d259f8269e551c64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5b75998316104f379d131d55957ff1.png)
(2)根据(1)的判断结果及表中数据,建立
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cd40bb3c1159beb697abfb5e5f5544a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a87796ee30e6c5d5e6b6285b32abe10c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/900206075ce8f1f040d2e3a6685ad51a.png)
附:对于一组数据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eafbe64ec9acf78f3624abbd06d516e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1db6103cb0f1d2bd6b19235d53ee7e98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/446c21b8025405469a473aa0b32f9373.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07ae0b4264da6a8812454ffd2f20d94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
经济前景等级 | 悲观 | 尚可 | 乐观 | |||||||
问卷得分 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
频数 | 2 | 3 | 5 | 10 | 19 | 24 | 17 | 9 | 7 | 4 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
(1)该杂志记者又随机访问了两名业内人士,试估计至少有一人预测中国经济前景为“乐观”的概率;
(2)某人有一笔资金,现有两个备选的投资意向:物联网项目或人工智能项目,两种投资项目的年回报率都与中国经济前景等级有关,根据经验,大致关系如下(正数表示赢利,负数表示亏损):
经济前景等级 | 乐观 | 尚可 | 悲观 |
物联网项目年回报率(%) | 12 | 4 | ![]() |
人工智能项目年回报率(%) | 7 | 5 | ![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
(1)求顾客甲在一次游戏中正面朝上次数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b734e8f1546481e3eb4976008a045de.png)
(2)若连续参加游戏获得的分数总和不小于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d0b71b8d2c183154221f717ce09077b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
如下:
日期 | 第一天 | 第二天 | 第三天 | 第四天 | 第五天 | 第六天 | 第七天 |
日期代码![]() | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
杯数![]() | 4 | 15 | 22 | 26 | 29 | 31 | 32 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6a5b1c19e4c57f1d259f8269e551c64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/357538995534570800ea9a3f93e49e34.png)
(3)若每天售出至少25杯即可盈利,则从第一天至第七天中任选三天,记随机变量X表示盈利的天数,求随机变量X的分布列.
参考公式和数据:其中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cbe3b764284e1033260803f839e8d2f.png)
回归直线方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1db6103cb0f1d2bd6b19235d53ee7e98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe8f5ca3171c709a7d16356183926462.png)
![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
22.7 | 1.2 | 759 | 235.1 | 13.2 | 8.2 |