Index
A statistic which assigns a single number to several individual statistics in order to quantify trends. The best-known index inthe United States is the consumer price index, which gives a sort of ``average'' value for inflation based on the price changesfor a group of selected products.
Let 
be the price per unit in period 
, 
be the quantity produced in period , and 
be the valueof the units. Let 
be the estimated relative importance of a product. There are several types of indices defined,among them those listed in the following table.
| Index | Abbr. | Formula |
| Bowley Index |  |  |
| Fisher Index |  |  |
| Geometric Mean Index |  |  |
| Harmonic Mean Index |  |  |
| Laspeyres' Index |  |  |
| Marshall-Edgeworth Index |  |  |
| Mitchell Index |  |  |
| Paasche's Index |  |  |
| Walsh Index |  |  |
References
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.
- Number
- Number Axis
- Number Field
- Number Field Sieve Factorization Method
- Number Group
- Number Guessing
- Number Pyramid
- Number System
- Number Theoretic Transform
- Number Theory
- Number Triangle
- Number Wall
- Numerator
- Numerical Derivative
- Numerical Integration
- Numeric Function
- Numerology
- NURBS Curve
- NURBS Surface
- Nyquist Frequency
- Nyquist Sampling
- Néron-Severi Group
- Nöther
- Obelus
- Object