Similar to how timechart sum() by ip | addtotals
which adds a "Totals" Column to a timechart, how can you add an averages column?
I don't think there is a native way to get that. Try this workaround
... timechart sum(..) by ip | eval count=0 | foreach * [eval count=count+1] | addtotals | eval Average=Totals/count
This worked perfect for me