I have a year's worth of daily sales volume of 8 items each identified by a code ItemNbr across 100 different stores each identified by a code StoreNbr. What I would like to do is calculate a 7 day moving average on an ItemNbr-StoreNbr basis. The moving avg. formula is as below. How can I group that on an ItemNbr-StoreNbr basis?

Any help would be greatly appreciated. Happy to share a copy of the file if that would be helpful.

MA Avg. Formula:

Mean(:POSQty[Row() - 3,Empty()], :POSQty[Row() - 2,Empty()], :POSQty[Row() - 1,Empty()], :POSQty[Row(),Empty()], :POSQty[Row() + 1,Empty()], :POSQty[Row() + 2,Empty()], :POSQty[Row() + 3,Empty()])