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=AVERAGE(IF(A1:A1020,B1:B10))

Adjust for your data

HTH

"lapark" wrote:

Using data from a separate spreadsheet, I am trying to calculate an average
based on criteria in another column in EXCEL. Here is an example, if results
are 20, then how do I calculate average age? Spreadsheet (1) is call all
results and Spreadsheet (2) is called scores20

A1=21 B1=18
A2=25 B2=15
A3=18 B316
A4=16 B4=15
A5=15 B5=14
A6=10 B6=19
A7=23 B7=14
A8=24 B8=17
A9=22 B9=16
A10=12 B10=15