Yesterday each of 35 么member of a certain task force spent some time working on project P, the graph shows the number of hours and the number of members who spent that number of hours on project P yesterday. what was the median number of hours that the members of the task force spent working on project P yesterday?

A.2 B.3 C.4 D.5 E.6 (answer is E)

图表内容显示：花一个小时的人9个，花两个小时的人4个，花三个小时的人1个，花四个小时的人2个，花五个小时的人1个，花六个小时的人8个，花七个小时的人10个，总数35个人。

为什么选E呢？望NNs指点。

median number 是中间数而不是平均数。

The median is the middle number. To calculate the median of any set of numbers you need to write the numbers in order. The median is the middle number.

Kieran's results were:

10 14 10 12 10 11 12 10 11 9 12

The Answer

Put the numbers in order:
9 10 10 10 10 11 11 12 12 12 14

Find the middle number:
9 10 10 10 10 11 11 12 12 12 14

The middle number is 11, so the median is 11.

Remember to find the median number you have t

• Put all the numbers in numerical order
• If there are an odd number of results (as above), the median is the middle number
• If there are an even number of results, the median will be the mean of the two central numbers

Finding the median with an even number of results

Question 2

Find the median of the numbers: 5 11 12 4 8 21

The Answer

Here's how to find the median number:

Put the results in order:
4 5 8 11 12 21

Find the middle number or numbers:
4 5 8 11 12 21

If there are two central numbers, we need to find their mean.

The median is therefore:

35的中间是18。所以按所花时间由小到大 或由大到小排列35个人。第18个人所花的时间就数中间数。

median number 的概念在最基本的统计里面有。找本英文版的统计课本翻一下就行了。