I'm trying to write a formula to return the AVERAGE by calendar quarter, IF
the quarter has ended.
For instance, IF Jan = 5, Feb = 20, Mar 5, Average would be 10.
But, if Mar was 0 (only meaning no activity) I still need it to calculate.

The formula I started with is -
=IF(A1=0,0,AVERAGE(A1:A3)

This works only if cells A1:A3 have a value greater than 0. How can I write
the formula so that as long as A3 is not blank that it will return the
AVERAGE?

Thanks!