Question: The Help Desk for online classes takes calls from students needing assistance with the technical functionality of their class. The duration of these calls is normally distributed and has historically averaged 540 seconds (9 minutes). As a new call center supervisor you randomly sample 16 calls and find the average length to be 510 seconds with a standard deviation of 45 seconds. Can you conclude that the population mean is no longer 540 seconds, at the 1% level of significance?