Rolling Average - Needs to be validated please

For each sprint this will work out the average over this sprint and the subsequent 2 sprints, is this what you are trying to do? Usually rolling averages are calculated using the previous values, i.e. this sprint and the 2 immediately prior to it.

Also, this will break if any sprints are filtered out e.g. by slicers, given that it is dependent on the iteration number increasing by 1 each time.

Rolling Average =
VAR NumSprints = 3
VAR RollingAvg =
    CALCULATE (
        AVERAGE ( 'Agile Metrics View'[Story Points] ),
        FILTER (
            ALLSELECTED ( 'Agile Metrics View' ),
            'Agile Metrics View'[Iteration Number]
                <= SELECTEDVALUE ( 'Agile Metrics View'[Iteration Number] )
                && 'Agile Metrics View'[Iteration Number]
                    > SELECTEDVALUE ( 'Agile Metrics View'[Iteration Number] ) - NumSprints
        )
    )
RETURN
    RollingAvg