These are the bottom 20 performing stores when products were not promoted. These stores accounted for only 14% of total unit sales. We also see that more than half of these stores belong to store class C.
The unit sales by store & weekday graph on the lower left-hand corner of the screen highlights the difference between unit sales (the colored circles) between stores on a given day. As during the promotion, "problem stores" within each store class are the ones whose circles representing daily sales are closer to the left-hand side of the graph.
The indexed DSI by weekday graphic shows that about half of the stores performed at between 60% and 80% of the level of the "Top 20" stores on a given weekday, and the other half performed at a much lower level รณ between under 10% and around 40% of the "Top 20" stores.