作者ahold (Saatch aur Himmat.)
看板GMAT
标题Re: [计量] pp1 请教
时间Mon Sep 14 00:42:57 2009
原题有12个数据：
7.51、8.22、7.86、8.36、8.09、7.83
8.30、8.01、7.73、8.25、7.96、8.53
看有几个在"1.5"个标准差的范围内就好了
所以要在7.65～8.55的范围内！
答案是11个没错吧？
※ 引述《a2515125 (Bobshih)》之铭言：
: A vending machine is designed to dispense 8 ounces of coffee into a cup.
: After a test that recorded the number of ounces of coffee in each of 1,000
: cups dispensed by the vending machine, the 12 listed amounts, in ounces,
: were selected from the data. If the 1,000 recorded amounts have a mean
: of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12
: listed amounts are within 1.5 standard deviations of the mean?
: (A) Four
: (B) Six
: (C) Nine
: (D) Ten
: (E) Eleven
: 请问这题如何解?
: SD=0.3
: Mean=8.1
: 范围7.8~8.4
: 然後呢~"~
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