=average(if(b1:b100)=1,a1:a100))

This is an array formula. Hit ctrl-shift-enter instead of enter. If you do it
correctly, excel will wrap curly brackets {} around your formula. (don't type
them yourself.)

Adjust the range to match--but you can't use the whole column.

vinnie123 wrote:

Hi everyone. I've a spreadsheet with one column (eg. A1:A100)
containing a range of values (ages) and another column (B1:B100) a
value of either 1 or 2 (representing males vs females). How can a find
the average of the cells A1:A100 that have a value of 1 in column B;
ie. the average age of the males only

Any suggestions? Thanks.

--

Dave Peterson