To investigate the youth use of the Internet, a sample of 8 adults was asked to report the number of hours they spent on the Internet during the last month. The results are listed below:

7, 14, 6, 15, 4, 13, 9, 12.

The researchers claim that the number of hours the adults spent on the Internet exceeds 15 hours per month.

1. Find the point estimator of the mean () for the number of hours the adults spent on the Internet per month.
2. State and conduct a 5-step test of hypotheses to investigate the researchers claim. Use

=0.05. Assume that the population variance is 16.