DAX for calculating a running average over defined days, including filtering out dates

hey.  thanks so much for responding... unlike in the simple model you attached, I didn't have the data/value that was being averaged in the same table as the one being used for the date field; I was using a separate table for my dates (model is much more complex, with mulitple table relying on one date table that I use in a single direction filtering context; in my DAX formula, I moved all my references to the table that had the value being averaged, and it worked.  thanks for your help man!