Pat watched TV last week

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Pat watched TV last week

by sanju09 » Wed Apr 08, 2009 5:11 am
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?
A. 30
B. 20
C. 18
D. 12
E. 6


OA D
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by scoobydooby » Wed Apr 08, 2009 5:49 am
SD-1mean= 21-6=15
SD-2 mean=21-12=9

pats hours must lie betweeb 9 and 15.
the only choice that satisfies this is 12

hence D