what is meant by an ‘ index number’ explain its main features. in 250 words
Answers
Explanation:
An index number is the measure of change in a variable (or group of variables) over time. ... Index numbers are not directly measurable, but represent general, relative changes. They are typically expressed as percents.
Answer:
An index number is the measure of change in a variable (or group of variables) over time. It is typically
used in economics to measure trends in a wide variety of areas including: stock market prices, cost of living,
industrial or agricultural production, and imports. Index numbers are one of the most used statistical tools
in economics.
Index numbers are not directly measurable, but represent general, relative changes. They are typically
expressed as percents.
Features of Index numbers:
The following are the main features of index numbers:
(i) Index numbers are a special type of average. Whereas mean, median and mode measure the absolute
changes and are used to compare only those series which are expressed in the same units, the technique of
index numbers is used to measure the relative changes in the level of a phenomenon where the measurement
of absolute change is not possible and the series are expressed in different types of items.
(ii) Index numbers are meant to study the changes in the effects of such factors which cannot be measured
directly. For example, the general price level is an imaginary concept and is not capable of direct
measurement. But, through the technique of index numbers, it is possible to have an idea of relative changes
in the general level of prices by measuring relative changes in the price level of different commodities.
(iii) The technique of index numbers measures changes in one variable or group of related variables. For
example, one variable can be the price of wheat, and group of variables can be the price of sugar, the price
of milk and the price of rice.
(iv) The technique of index numbers is used to compare the levels of a phenomenon on a certain date with
its level on some previous date (e.g., the price level in 1980 as compared to that in 1960 taken as the base
year) or the levels of a phenomenon at different places on the same date (e.g., the price level in India in
1980 in comparison with that in other countries in 1980).
Steps or Problems in the Construction of Price Index Numbers:
The construction of the price index numbers involves the following steps or problems:
1. Selection of Base Year:
The first step or the problem in preparing the index numbers is the selection of the base year. The base year
is defined as that year with reference to which the price changes in other years are compared and expressed
as percentages. The base year should be a normal year.
2. Selection of Commodities:
The second problem in the construction of index numbers is the selection of the commodities. Since all
commodities cannot be included, only representative commodities should be selected keeping in view the
purpose and type of the index number.
In selecting items, the following points are to be kept in mind:
(a) The items should be representative of the tastes, habits and customs of the people.
(b) Items should be recognizable,
(c) Items should be stable in quality over two different periods and places.
(d) The economic and social importance of various items should be considered
3. Collection of Prices:
After selecting the commodities, the next problem is regarding the collection of their prices:
(a) From where the prices to be collected;
(b) Whether to choose wholesale prices or retail prices;
(c) Whether to include taxes in the prices or not etc.