Provide an appropriate response. The manager of a bank recorded the amount of time each customer spent waiting in line during peak business hours one Monday. The frequency distribution below summarizes the results. Find the standard deviation. Round your answer to one decimal place. Waiting time Number of (minutes) customer 0-under 4 8 4-under 8 15 8-under 12 13 12-under 16 11 16-under 20 0 20-under 24 3 5.5 5.2 4.9 7.0