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陈月麟

.DS: 45% the apartments with <=3 people living in each one. What’s the median? (1)80% of the apartments have <=5 (2)35% of the apartments have >=5 ###(C) Note: Median is 4

陈月麟

PG, 谢谢！
I understand it now. Becos I thought 50% is frequency.所以才搞错了。
Becos {3,3,3,(there are 45% of them), .4...} and we must look for where 50% is - correct?

pgclt

Make sure you understand Median is the middle number (or average of middle two numbers) of an ORDERDED set. I had same ambuigity a few weeks ago.

e.g., sequence: 4, 2, 3, 5, 1, 6, 7.
to get its median, you need to order it first: 1,2,3,4,5,6,7
then its median is 4.

Mode is the most frequent number of the sequence. e.g., 如果答案是50%=4的话，那4是 MODE.  Range is the difference between maximum and minimum.

陈月麟

我已经想通了，浪费大家的宝贵时间，真抱歉！

陈月麟

公主，谢谢您的解答！

如果答案是50%=4的话，那4是 MODE而不是 MEDIAN。
因为4占最高的百分率（50%）。对吗？ 还是我的理解有错误？

princess

这个数轴贴出来以后全走样了：（还改不了
那两个逗号分别代表45％和65％这两点
最上面那行表示三段区间的取值范围

将就着看看吧

princess

可以花一个数轴 <=3 4 >=5 ——’——‘——> 45％ 50％ 65％ 求median其实就是看50%这点上的数 combine（1）and（2）,45%到65%这一段是都是4，所以50%这一点上肯定也是4

[此贴子已经被作者于2002-10-16 11:06:41编辑过]

[此贴子已经被作者于2002-10-16 11:08:29编辑过]

陈月麟

谢谢PG为我解答！ But I still do not understand: (1)Median is middle number in data set (2)<=5, is 80%, so remainder 20% could be 6,7,8,..etc (3)So, which is median, we cannot determine. Pls help!

arrymin

还是不明白[em27],[em09]

chen yue lin, do you understand?

pgclt

DS: 45% the apartments with <=3 people living in each one. What’s the median? 1)80% of the apartments have <=5 (2)35% of the apartments have >=5 ###(C) Note: Median is 4 条件（1）- 中数可为4，5，等， 条件（2）- 从这里可以算出 15% 为5人户口. ------------------------------------- so far you steps are good. Next, since 15% has 5 people. combine with 1), we can get 65% has < 5. which equals to 65% <= 4; then combine with original condition: 45% <= 3 in the statement, the median has to be 4.