请教GMAT PREP中的一道题(题目已经重新贴上)

luckier

[此贴子已经被作者于2006-3-29 23:30:44编辑过]

hitlzc

题目看不到

luckier

The residents of Town X participated in a

survey to determine the number of hours per week each resident spent watching

TV. The distribution of the results of the survey had a mean of 21 hours and a

standard deviation of 6 hours. The number of hours that Pat, a resident of Town

X, watched TV last week was between 1 and 2 standard deviations below the mean.

Which of the following could be the number of hours that Pat watched TV last

week?  30; 20; 18; 12; 6. The answer is D, but I choose C.....Thank you.

[此贴子已经被作者于2006-3-30 12:58:12编辑过]

hitlzc

a resident of Town
X, watched TV last week was between 1 and 2 standard deviations below the mean.

即范围在21-2*6到21-1*6这个范围内。

9到15之间。按你给的选项就选E了。你的选项D好像写错了，我记得看到过，好像是12

luckier

谢谢斑竹。第四个选项已经改过来了。我还是太粗心了。