Question 2: Many companies are increasingly concerned about
computer security and employees using their computers for
personal use. A random sample of 50 employees of Liberty Mutual
Insurance Company was obtained, and each was asked whether
they use the Internet for personal purposes during the day. The
average of hours for the 50 employees is 0.722. Assume the
population standard deviation is 0.5 hours.
a.
Find an 95% confidence interval for the mean number of hours all
employees at Liberty Mutual use the internet for personal reasons.
b.
Using the confidence interval in part (a), is there any evidence to
suggest that the mean time spent using the Internet for personal
reasons is more than 1 hour? Justify your answer.
c.
How large a sample is necessary in order for the bound on the error
of estimation to be 0.1 hours?
