The service manager wants to make sure that no one waits longer than 18 minutes. Determine the standard deviation that would be required to meet this goal.
Recently, the manager at Micron conducted a study of the time customers spent on hold waiting for a Micron representative to become available. The data showed that the distribution of time spent on hold is approximately normally distributed, with a mean of 18 minutes and a standard deviation of 4 minutes. Question: The servic