A study of two hundred teens found that the number of hours they spend on social networking sites each week ...

Question

anonymous · Answer

A study of two hundred teens found that the number of hours they spend on social networking sites each week is normally distributed with a mean of 12 hours. The population standard deviation is 4 hours. What is the margin of error for a 98% confidence interval? 

 0.122 

 0.659 

 0.295 

 0.313

anonymous · Answer

Definition of "margin of error"?

Looks like these are uncertainties regarding the mean,
which are measured in terms of multiples of the standard error
of the mean SE = SD/sqrt(n) = 4/sqrt(200) = 0.283.

To have 98% use mean +- 2.04 SE = mean +- .577,
which is not close to your options. I'm puzzled.