Hello,
I would use a Pivot Table.
For example select cell D1 Go to the Insert tab and click Pivot Table.
Select your range Sheet1!$A$1:$B$9 and click OK.
Then in the right hand pane, pull column A into the Row labels section and the B column in to the Values section.
Click on the Sum of B in the Values section and select Value Field Settings then Average.
I hope this helps.
Cheers,
Diana
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