Text Messaging. A telecommunications company wants to estimate the mean length of time (in minutes) that 18-to 24-year-olds spend text messaging each day. In a random sample of twenty-seven 18-to 24-year-olds, the mean length of time spent text messaging was 29 minutes. From past studies, the company assumes that s is 4.5 minutes and that the population of times is normally distributed.

Determine a 95% confidence interval for the population mean.