Weighted price index

Weighted price index
The price index constructed by giving different weights to different commodities is called weighted price index.  Weights are given on the basis of regularity in consumption and the amount spent and the number of consumers.  The commodities consumed by all or majority of consumers spending large amount of income is given more weights and vive versa. The average price is calculated dividing the sum of weighted price by sum of weights.
weighted average price = sum of weighted prices / sum of weights
The major methods of weighted price index are fisher’s method, Laspeyre’s method, Pasche’s method etc. Weighted price index is calculated under
We can explain it with the help of table as following

commoditiesWeight (W)Price in 2011 (P1)P1*WPrice in 2012 (P2)P2*W
Rice10Rs 35Rs 350Rs 40Rs 400
Pulses4Rs 80Rs 320Rs 95Rs 380
Clothes3Rs 250Rs 750Rs 275Rs. 825
Vegetables5Rs 50Rs  250Rs 70Rs 350
Firewood2Rs 100Rs 200Rs 150Rs 300
total24Rs 515Rs 1870Rs 630Rs 2255
Price index100120.58

In the above table, we have taken only 5 commodities.  Sum of the weighted prices of the base year 2011 is Rs 1870. The sum of weighted price of 2012 is Rs 2255. If we divide these sums of weighted prices by the sum of weights we obtain average price of the year2011 as Rs 77.92 and of the year 2012 Rs 93.95. Indexing price level of base year as 100 we can obtain the price index of the year 2012 as 1220.58. There is said to be rise in price level by 20.58%.