A study of three hundred teenagers found that the number of hours they spend on instant messaging sites each week is normally distributed with a mean of 13 hours. The population standard deviation is 5 hours. What is the margin of error for a 99% confidence interval?

0.743
0.334
0.320
0.413

Question

A study of three hundred teenagers found that the number of hours they spend on instant messaging sites each week is normally distributed with a mean of 13 hours. The population standard deviation is 5 hours. What is the margin of error for a 99% confidence interval?

 0.743 
0.334 
0.320 
0.413

debbieg · Answer

Do you know the formula for the margin of error?

hayhayz · Answer

Nope im not sure how to do this :/

debbieg · Answer

Do you know the formula for the confidence interval? X-bar +/- {something}? If you are doing this topic, you must have learned the formula. The margin of error is the part that you add/subtract to the sample mean, to get the C.I.