Page:Stabilizing the dollar, Fisher, 1920.djvu/57

1] is known as a "weighted" average. If, reversely, beef is "weighted" twice as much as wheat, the average rise is $$\frac{4+4+10}{3}=8$$ and the index number is 108. It will be noted that there is remarkably little difference between the "weighted" averages on the one hand (106 and 108), and the "unweighted" average (107) on the other. Such is usually the case. Figure 1 illustrates this important fact. Nor does it generally make

much difference whether very many or only a moderate number of commodities are included. Figure 2 illustrates this fact.

On the whole, the best form of index number is that expressing the price of a given bill of goods. If a