An Internet server conducted a survey of 400 of its customers and found that the average amount of time spent online was 12.5 hours per week with a standard deviation of 5.4 hours.
1. Do you think that the random variable x, the number of hours spent online, has a mound-shaped distribution? If not, what shape do you expect?
2. If the distribution of the original measurements is not normal, you can still use the standard normal distribution to construct a confidence interval for , the average online time for all users of this Internet server. Why?
3. Construct a 95% confidence interval for the average online time for all users of the particular Internet server.
4. If the Internet server claimed that its users averaged 15 hours of use per week, would you agree or disagree? Explain.