数学OG13 139题，求讲解

SharonZ0902

129. What is the median number of employees assigned
per project for the projects at Company Z ?
(1) 25 percent of the projects at Company Z have 4
or more employees assigned to each project.
(2) 35 percent of the projects at Company Z have 2
or fewer employees assigned to each project
正选C
这里的median number是指的员工人数的中位数？答案我看的不是很明白，我想关键是我不知道哪个中位数是怎么算出来的吧
1
Although 25 percent of the projects have 4 or more employees, there is essentially no information about the middle values of the numbers of employees per project. For example, if there were a total of 100 projects, then the median could be 2 (75 projects that have exactly 2 employees each and 25 projects that have exactly 4 employees each) or the median could be 3 (75 projects that have exactly 3 employees each and 25 projects that have exactly 4 employees each); NOT suffi cient
求解释。谢谢

zxc1118zxc

Median number, that the average number,

25% is 4 or above 4,
35% is below 2, that 1 or 2
so, the remaining 40% is 3, since 1-25%-35% is 40%

as a result, the median should be 3,

since the 25% above 4 is balanced with 25% of 1 or 2,
the remaining 10% of 1 or 2 is balanced with 10% of 3,
the remaining 30% is 3, that's where the median should be in.

norwaywinter

median number意思形象的说

假设一共100个projects，然后按照每个projects需要的人数从小到大排列，那么第五十个project需要几个人。。。

题目是说，条件1：前35个projects，不是需要1个人就是需要2个人，
        条件2：后25个projects需要4以上的人数，但是中间低36到底74都是需要3个人的。。。

        所以第五十个project是需要3个人的。。。

不知道说的形象化不。。。

SharonZ0902

谢啦，很清楚，要是开始遇见这个死定了，方法我了解了，题目就这么读的话还是不知道在讲什么呀~对着你的答案才看懂了点点，还需体会吧