A study of one thousand teens found that the number of hours they spend on social networking sites each week is normally distributed with a mean of 20 hours. The population standard deviation is 2 hours. What is the 95% confidence interval for the mean?

19.88−20.12 hours

19.76−10.24 hours

19.88−20 hours

20−20.12 hours

Question

A study of one thousand teens found that the number of hours they spend on social networking sites each week is normally distributed with a mean of 20 hours. The population standard deviation is 2 hours. What is the 95% confidence interval for the mean?

 19.88−20.12 hours

 19.76−10.24 hours

 19.88−20 hours

 20−20.12 hours

anonymous · Answer

I think it would be the  19.88−20.12 hours first because of the 95%... It would not be c because C does not go both ways, same with D.... as for B, the range is too wide in my opinion, but if A is not correct then the answer would probably be B