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题库 / Prep2007E2-DS-115
List S and list T each contain 5 positive integers, and for each list the average (arithmetic mean) of the integers in the list is 40. If the integers 30, 40, and 50 are in both lists, is the standard deviation of the integers in list S greater than the standard deviation of the integers in list T ?
(1) The integer 25 is in list S.
(2) The integer 45 is in list T.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
还没有题目讲解（毕出老师会陆续发布对官方考题的解读，请保持关注）。
20,40,50,25，总共5个数，知道4个数还知道平均数，可以把第5个数求出来！第5个数是知道的！并不是未知的！
each contains 5 integers
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