Circulation: Use Regression Analysis to Optimize Catalog Circ and Sales Data

So the East Coast regression analysis predicts a 5.9 percent increase in sales for every 8 percent discount offered. But on the West Coast, there will be only a 2.1 percent increase in sales for the same amount of discount, which doesn’t make sense at all. Remember, the sales increase averages are almost the same -- 8.89 percent vs. 9.17 percent. What’s wrong?