作者minimumi (米尼)
看板GMAT
标题[计量] PP1-PS-Q121
时间Fri Nov 16 16:01:29 2007
121.(E)
7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53
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
想请问ㄧ下这题应该怎麽解
谢谢~
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