Meaning and Definitions of Index Number
The index numbers are the special type of averages which are presented in percentages and computed on certain base.
Some important definitions
Murray Spiegal says an index number is a statistical measure designed to show changes in variable or group of related variables. With respect to time, geographic location or other characteristics,
Croxton and Cowden say Index numbers are decries for measuring differences in the magnitude of a group of related variables
Horace Sacrist says Index numbers are a series of numbers by which changes in the magnitude of phenomena are measured from time to time or from place to place.
T. W. Wonnacott and Ronald J. Wonnacott: An index number is a single figure showing how a whole set of related variable has changed over time to time of differs from place to place.
Dr, A. L. Bowely says: A series of index numbers is a series which effects in its trend and fluctuations the movement of some quantity to which it is related.
Wessel, Willett and says; An index number is a special type of average that p[provides a measurement of relative changes from time to time or from place to place.
It is evident from the above definitions that index number are special type of averages which the changes in a group of related variable over a period of time.