In the door-to-door selling of vacuum cleaners, various factors influence sales. The Birk Vacuum Cleaner Company considers its sales pitch and overall package to be extremely important. As a result, it often thinks of new ways to sell its product. Because the company’s management develops so many new sales pitches each year, there is a two-stage testing process. In stage 1, a new plan is tested with a relatively small sample. If there is sufficient evidence that the plan increases sales, a second, considerably larger, test is undertaken. In a stage 1 test to determine whether the inclusion of a “free” 10 -year service contract increases sales, 100 sales representatives were selected at random from the company’s list of several thousand. The monthly sales of these representatives were recorded for 1 month before the use of the new sales pitch and for 1 month after its introduction. Should the company proceed to stage 2?