A mattress company has two stores, one in City X and the other in City Z. The company has advertised equally in newspapers in both cities, but has advertised twice as much on the radio in City Z as in City X. The two cities have similar populations and economies and the sales at each store have been roughly equal. A consultant claims this shows that the radio advertising has not improved mattress sales.

In the table, select changes that the company could make in City X and City Z, respectively, that together would probably be most helpful in testing the consultant's claim. Make only two selections, one in each column.