According to the IRS, taxpayers calling the IRS in $2017$ waited $13$ minutes on average for an IRS telephone assister to answer. Do callers who use the IRS help line early in the day have a shorter wait? Suppose a sample of $50$ callers who placed their calls to the IRS in the first $30$ minutes that the line is open during the day have a mean waiting time of $11$ minutes before an IRS telephone assister answers.