18. [Example 2: Confidence Interval (TI-84 Plus)] internet in an average week. The sample mean was 8.20 hours, with a sample standard deviation of 9.84 hours. Assume this is a simple random sample from the population. A sample of 123 people aged 18-22 reported the number of hours they spent on Construct a 98% confidence interval for u, the population mean number of hours per week spent on the internet in that age group. Degrees of Area in the Right Tail Freedom 0.025 0.01 0.005 0.0025 100 1.984 2.364 2.626 2.871 95% 98% 99% 99.5% Confidence Level Formula: Confident Interval of population mean : (X-m)>u