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by shrutee » Thu Sep 22, 2011 7:34 am
The residents of town x participated in a survey to determine the number of hours per week each resident spent watching television.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 television 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 television last week?

1)30
2)20
3)18
4)12
5)6
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by gmatclubmember » Thu Sep 22, 2011 7:58 am
shrutee wrote:The residents of town x participated in a survey to determine the number of hours per week each resident spent watching television.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 television 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 television last week?

1)30
2)20
3)18
4)12
5)6

Pat watched tv b/w 1 or 2 sd below mean.
1 sd below mean would be 21-1*(6)= 15
2 sd below mean would be 21-2*(6)= 9
between 9 and 15, answer choice 4 or D( which is 12) falls.
So OA is 4. (D)

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