A study of five hundred adults found that the number of hours they spend on social networking sites each week is normally distributed with a mean of 14 hours. The population standard deviation is 3 hours. What is the margin of error for a 95% confidence interval?

A. 0.134
B. 0.220
C. 0.263
D. 0.313

Question

A study of five hundred adults found that the number of hours they spend on social networking sites each week is normally distributed with a mean of 14 hours. The population standard deviation is 3 hours. What is the margin of error for a 95% confidence interval?

A. 0.134
B. 0.220
C. 0.263
D. 0.313

jim_thompson5910 · Answer

Use the formula

ME = z*sigma/sqrt(n)


ME = margin of error
z = critical value (based on the confidence level)
sigma = population standard deviation
n = sample size

anonymous · Answer

Thank you very much :)

jim_thompson5910 · Answer

tell me what you get

anonymous · Answer

Would the formula look like: ME=95*3/sqrt(500) ?

jim_thompson5910 · Answer

everything is good but z is NOT 95

jim_thompson5910 · Answer

If you have a normal distribution

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jim_thompson5910 · Answer

then 95% of the data is from -k to +k

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