Average price analysis

[Derrick]

I'm analysing the average price of product ranges (each
product range will incl a series of products) across two
periods. I would like to filter out possible volume
effects (change in average price as result of change in
sales vol), pricing effects (change in average price as
result of change in price), and cross vol/price effects
(contribution of each product to the average price).

I've done up one spreadsheet but not exactly sure if I've
done it correctly. I would greatly appreciate any advise
on this.

Thanks!!