求助请教一道我读不懂的题，多谢！！！

JGMATJ · 发表于 2011-3-13 16:59:07

这题我读都读不懂。。。。。请高手指教。。。。。

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 standard deviation of 0.3 ounce, how many of the 12 listed amounts are within 1.5 standard deviations of the mean?

答案是11.

多谢多谢！！！！！

backlighting · 发表于 2011-3-13 17:12:10

kaji29 的解答
within 1.5 sd means 0.3*1.5=0.45
mean is 8.1
within 1.5 is between (8.1-0.45) and (8.1+0.45) OR:
7.65 < x < 8.55
only one doesn't fit, so 12 - 1 = 11
...................................................................
你可以自己试试在论坛里搜索，速度快点，好多NN的思路真的好好。

JGMATJ · 发表于 2011-3-13 17:32:53

非常感谢您backlighting！！！！！！好人！！！搜索当然速度快点，没想过有人写过同样的问题！！多谢指点！！
可能我比自己意识到的还要弱。。。我刚才试着搜索，可自己什么也没搜到！沮丧。请问您是怎样正确搜索到同样一题的?!? 多谢！！！！！！

backlighting · 发表于 2011-3-13 17:44:47

呃，就是把题目里比较明显的语句复制到搜索框里面，搜索“主题内容”，然后基本就都出来啦
我也才学会的说

JGMATJ · 发表于 2011-3-13 17:55:06

哦！！太好了！我自己用题第一句搜的，没结果，去沮丧了。现在听你一讲，就用题最一句搜，果然找到啦！！！感谢感谢感谢感谢感谢！！！！backlighting真是大好人！！！！！

求助请教一道我读不懂的题，多谢！！！

所属分类: GMAT考试

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