The regularized average of the value of relatives for an allocated class of goods or services in a specific region, during a mentioned period of time is called Price Index. This is statistically designed which can help to relate how the rates of relatives, considered to be a complete, varies from time frame or location to location. Copy the link given below and paste it in new browser window to get more information on Price Index:- http://www.transtutors.com/homework-help/economics/price-index.aspx