The number of sleep hours for adults is normally distributed with mean 7 hours and standard...
The number of sleep hours for adults is normally distributed with mean 7 hours and standard deviation 1.7 hours. How large a sample should be selected if we we wish our estimate to be correct within 30 minutes with 95% confidence?
a) 44
b)45
c)12
d)11
Homework Answers
Solution :
Given that,
standard deviation = 
= 1.7
margin of error = E = 0.5
Z
/2
= 1.96
Sample size = n = ((Z/2
*
) / E)2
= ((1.96 * 1.7) / 0.5)2
= 45
Sample size = 45
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