Discussion:
The number of staff personnel needed to handle patients at a medical center is determined by the mean time that patients must wait before being attended to by a physician. For a random sample of 100 previously recorded emergencies, the sample mean waiting time was 72 minutes, with a standard deviation of 28 minutes.
a. What is a 50 percent confidence interval for the actual mean waiting time?
b. What is a 99 percent confidence interval for the actual mean waiting time?