Monthly average greater than the largest single input. Why?

[newhopepdx]

I have started an event attendance report showing total attendance by event date to various events and a bar graph showing the average monthly, quarterly or yearly total attendance per event date.

The event category slicer seems to be causing the issue. There are two event categories: Regular & Special.

The image below shows the problem: With "Select All" as the category filter the average is 847, while the largest single date attendance is 826. Weird!  If the slicer is set to Regular, the average is accurate. What could be causing this?

Here's a link to files: https://www.dropbox.com/scl/fo/nplilnajf5s5nnvaaathy/h?rlkey=gb19rx380m2k3t2mtolyp33h1&dl=0

Steve

[jdbuchanan71]

Can you just use

Average Attendance = AVERAGE ( 'Attendance'[Attendance] )

[jdbuchanan71]

Because you are taking the average at the venue level then adding those all up:

AverAttendance = 
    SUMX (
        VALUES ( 'Attendance'[Venue] ),
        CALCULATE ( AVERAGE ( 'Attendance'[Attendance] ) )
)

The first one is just the straight avg so you can see that it is correct at the venue level.  Then you add all those up and get 847.

[newhopepdx]

Ok, I see how that work, but then what is the proper measure definition?