题目
题型:不详难度:来源:
8)中度拥堵;T∈[8,10]严重拥堵,晚高峰时段,从某市交通指挥中心选取了市区20个交通路段,依据其交通指数数据绘制直方图如图所示.
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124505-54751.png)
(1)这20个路段轻度拥堵、中度拥堵的路段各有多少个?
(2)从这20个路段中随机抽出的3个路段,用X表示抽取的中度拥堵的路段的个数,求X的分布列及期望.
答案
解析
试题分析:(1)由频率分布直方图可知底
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124505-36005.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124505-36005.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124506-33467.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124506-91670.png)
试题解析:(1)由直方图得:轻度拥堵的路段个数是
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124506-37811.png)
中度拥堵的路段个数是
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124506-35897.png)
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124507-73106.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124507-74073.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124507-53267.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124508-41896.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124508-68624.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124508-27990.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124508-37298.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124507-73106.png)
![]() | 0 | 1 | 2 | 3 |
![]() | ![]() | ![]() | ![]() | ![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124509-54130.png)
核心考点
试题【交通指数是交通拥堵指数的简称,是综合反映道路网畅通或拥堵的概念,记交通指数为T.其范围为[0,10],分别有五个级别:T∈[0,2)畅通;T∈[2,4)基本畅通】;主要考察你对用样本的频率分布估计总体分布等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124502-33421.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124456-62644.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124456-39546.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124456-49872.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124457-29788.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124457-13496.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124457-53271.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124457-62237.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124457-90170.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124458-87247.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124458-19704.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124450-41453.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124450-22041.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124450-11871.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124443-69110.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124444-91806.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124444-48029.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124444-71528.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124445-16183.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124439-69986.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124440-53501.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124440-66450.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124440-22507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191026/20191026124440-33144.png)
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