The growing use of bicycles to commute to work has caused many cities to create exclusive bicycle lanes. These lanes are usually created by disallowing parking on streets that formerly allowed curbside parking. Merchants on such streets complain that the removal of parking will cause their businesses to suffer.

To examine this problem, the mayor of a large city decided to launch an experiment on one busy street that had 1-hour parking meters. The meters were removed and a bicycle lane was created. The mayor asked the three businesses (a dry cleaner, a doughnut shop, and a convenience store) in one block to record daily sales for two complete weeks (Sunday to Saturday) prior to the change and two complete weeks after the change. The data are stored as follows: column 1 = Day of the week; column 2 = Sales before change for dry cleaner; column 3 = Sales after change for dry cleaner; column 4 = Sales before change for doughnut shop; column 5 = Sales after change for doughnut shop; column 6 = Sales before change for convenience store; and column 7 = Sales after change for convenience store. What conclusions can you draw from these data?