Need help with DIV/0 error in an AVERAGE array formula

[Safety Jim]

I am using =AVERAGE(IF(isnumber(0(C3:C8)),0(C3:C8,"")) to calculate an
average % in a column with zero's and Excel is giving me a message that the
formula is incorrect. Can anyone help?

 

[Dave Peterson]

Maybe you meant:
=AVERAGE(IF(ISNUMBER(0+(C3:C8)),0+(C3:C8),""))
or
=AVERAGE(IF(ISNUMBER(C3:C8),C3:C8))

Be careful.

These formulas are not equivalent. Empty cells and cells containing text that
looks numeric are treated differently.

Remember that each of these are array formulas. 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.)