急求一道JJ数学题。在线等！！！！！！！！！！！！！！！！！！！！！！！！

fons · 发表于 2007-10-16 15:17:00

是道JJ题

S ，T 都是整数数列 S mean > T median吗？

1） S，T都是等长连续 odd even 数列。 2）mean S> mean T

这题该怎么做啊？ odd even 数列是什么意思？

kevinchy · 发表于 2007-10-16 15:20:00

可能意思是S是ODD数列,T是EVEN数列

sydneyang · 发表于 2007-10-16 15:37:00

Agree with LS

Statement 1 sounds like Set S is odd and Set T is even. Both have the same length and consecutive.

Personally, I would choose C:

Statement 1 is obviously not enough because no mean of S, T and no median is given.

Statement 2 is also not sufficient because they can be any number in the Sets.

Together we know the sets are consecutive numbers and Set S mean is greater than Set T mean.

For example: Set S=(3,5,7); Set T=(2,4,6). So S mean will be greater than T median.

Just my thoughts, not sure correct 与否。

fons · 发表于 2007-10-16 15:47:00

谢谢楼上两位！

spring32 · 发表于 2007-10-16 18:01:00

选哪一个？

我怎么感觉是b 呢？

raikey · 发表于 2007-10-16 21:09:00

选C,明白两点即可:
连续奇(或偶)数列是等差数列
等差数列的median=mean

fons · 发表于 2007-10-16 21:26:00

谢谢楼上！但是你那个第二点的前提应该是数列的term应该是奇数个。偶数个 mean 不等与 median

[此贴子已经被作者于2007-10-16 21:29:09编辑过]

raikey · 发表于 2007-10-16 21:34:00

不对,无论数列中元素的个数是奇是偶,等差数列的平均数≡中数.
要注意当元素个数为偶时,中数是最中间的那两个数的平均数!

fons · 发表于 2007-10-16 21:43:00

哦是的我糊涂了呵呵！

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