Index Number

A statistic which assigns a single number to several individual statistics in order to quantify trends. The best-known index in the United States is the consumer price index, which gives a sort of "average" value for inflation based on price changes for a group of selected products. The Dow Jones and NASDAQ indexes for the New York and American Stock Exchanges, respectively, are also index numbers.

Let p_n be the price per unit in period n, q_n be the quantity produced in period n, and v_n=p_nq_n be the value of the n units. Let q_a be the estimated relative importance of a product. There are several types of indices defined, among them those listed in the following table.

See also

Bowley Index, Fisher Index, Geometric Mean Index, Harmonic Mean Index, Laspeyres' Index, Marshall-Edgeworth Index, Mitchell Index, Paasche's Index, Walsh Index

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Fisher, I. The Making of Index Numbers: A Study of Their Varieties, Tests and Reliability, 3rd ed. New York: Augustus M. Kelly, 1967.Kenney, J. F. and Keeping, E. S. "Index Numbers." Ch. 5 in Mathematics of Statistics, Pt. 1, 3rd ed. Princeton, NJ: Van Nostrand, pp. 64-74, 1962.Mudgett, B. D. Index Numbers. New York: Wiley, 1951.

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Index Number

Cite this as:

Weisstein, Eric W. "Index Number." From MathWorld--A Wolfram Web Resource.

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