Town X and Standard Deviation

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Town X and Standard Deviation

by zagcollins » Mon Jul 28, 2008 11:22 pm
Residents of Town X participated in a survey to determine the no. of hrs per week each resident spent watching TV.The distribution of results of the survey had a mean of 21 hrs an a standard dev of 6 hrs. The no. of hrs that Pat, a resident of Town X, watched TV, last week was between 1 and 2 standard dev below mean. Which of the following could be the number of hrs that Pat watched TV last week?

A.30
B.20
C.18
D.12
E.6

OA is D
Last edited by zagcollins on Tue Jul 29, 2008 2:34 am, edited 1 time in total.
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by pepeprepa » Tue Jul 29, 2008 12:40 am
1 standard deviation: 6
2 standards deviation: 12

between 1 and 2 standard dev below mean so it is
between 21-12 et 21 - 6 so it is between 9 and 15

The only on epossibility is D)12