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 15 hours. The population standard deviation is 2 hours. What is the 95% confidence interval for the mean?
Accepted Solution
A:
2 standard deviations contain 95% confidence. So thus you would have 4hrs in either direction. So the interval at which we could feel 95% confident is between 11-19hrs.