Waiting times (in minutes) of customers at a bank where all customers enter a single waiting line and a bank where customers wait in individual lines at three different teller windows are listed below. Find the coefficient of variation for each of the two sets of data, then compare the variation.

Bank A (single line) Bank B (individual lines) 6.6 4.0 6.6 5.5 6.7 5.9 6.8 6.2 7.1 6.6 7.2 7.7 7.4 7.8 7.7 8.5 7.7 9.3 7.7 9.8