To average the odd columns:
=AVERAGE(IF(MOD(COLUMN(3:3)*ISNUMBER(3:3),2),3:3))

even columns:
=AVERAGE(IF((MOD(COLUMN(3:3),2)=0)*ISNUMBER(3:3),3 :3))

Both of these are array formulas, and should be confirmed using
Ctrl+Shift+Enter, not just Enter.
--
Best Regards,

Luke M
*Remember to click "yes" if this post helped you!*


"Mike" wrote:

I want to take the average of every other column in my data set and I will be
adding weeks to the data as time moves forward. Is there a relative or
absolute formula that does this?

Thanks for any help.