What is the Retail Price Index? [RDI] -How is it Calculated - what does it show? -How are the items even defined?

-The RDI is just a Measurement for Inflation. That's it -2 Surveys is needed. 1st is a Survey of 6K Homes [Living Costs & Food Survey] which finds out what people Spend their Money on, and what Proportion. This helps with the Weighting of each item [20% on Apples = 20% Weight] -Second Survey is on Prices, and just measures the Change of 700 most Commonly used Commodities [Basket of Goods] [These Items comes from the First Survey] -Price Changes are then Multiplied by the Weightings, and then Converted to an Index Number. Inflation is just the Percentage Change to the Index Number