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Research Methodology




                    Notes                                         Price in 1990 Price in 1992
                                                           Item
                                                                  (in Rs/unit)  (in Rs/unit)
                                                         1. Wheat  300/quintal  360/quintal
                                                         2. Rice     12/kg.     15/kg.
                                                         3. Milk    7/litre     8/litre
                                                         4. Eggs    11/dozen   12/dozen
                                                         5. Ghee    80/kg.      88/kg.
                                                         6. Sugar    9/kg.      10/kg.
                                                         7. Pulses  14/kg.      16/kg.
                                   The comparison of price of an item, say wheat, in 1992 with its price in 1990 can be done in two
                                   ways, explained below:

                                   1.  By taking the difference of prices in the two years, i.e., 360 - 300 = 60, one can say that the
                                       price of wheat has gone up by   60/quintal in 1992 as compared with its price in 1990.

                                                                         360
                                   2.  By taking the ratio of the two prices, i.e.,   = 1.20, one can say that if the price of wheat
                                                                         300
                                       in 1990  is taken to be  1, then  it has  become 1.20  in 1992.  A more  convenient way of
                                       comparing the  two  prices  is  to  express  the  price  ratio  in terms  of  percentage,  i.e.,
                                        360
                                           ´  100 =  120 , known as Price Relative of the  item. In our example, price relative of
                                        300
                                       wheat is 120 which can be interpreted as the price of wheat in 1992 when its price in 1990
                                       is taken as 100. Further, the figure 120 indicates that price of wheat has gone up by 120 – 100
                                       = 20% in 1992 as compared with its price in 1990.
                                   The first way of expressing the price change is inconvenient because the change in price depends
                                   upon the units in which it is quoted. This problem is taken care of in the second method, where
                                   price change is expressed in terms of percentage. An additional advantage of this method is that
                                   various price changes, expressed in percentage, are comparable. Further, it is very easy to grasp
                                   the 20% increase in price rather than the increase expressed as   60/quintal.
                                   For the construction of index number, we have to obtain the average price change for the group
                                   in 1992, usually termed as the Current Year, as compared with the price of 1990, usually called
                                   the Base Year. This  comparison can be done in two ways:
                                   1.  By taking suitable average of price relatives of different  items. The methods of  index
                                       number construction based on this procedure are termed  as Average of Price Relative
                                       Methods.
                                   2.  By taking ratio of the averages of the prices of different items in each year. These methods
                                       are popularly known as Aggregative Methods.
                                   Since the average in each of the above methods can be simple or weighted, these can further be
                                   divided as simple or weighted. Various methods of index number construction can be classified
                                   as shown below:

                                                           Methods of Index Number Construction


                                           Average of Price Relatives Methods      Aggregative Methods


                                       Simple Average      Weighted Average   Simple              Weighted
                                       of Price Relatives  of Price Relatives  Aggregative        Aggregative
                                       Methods             Methods            Methods             Methods




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