Hi, I will need anyones assistance on this please... Cant figure it out..

I have this formula that I use to compute averages given a criteria,
{=AVERAGE(IF((C3:C325M4), C3:C325))}

when I try to change it to {=AVERAGE(IF((C:CM4), C:C))}, it doesnt work because it takes into consideration all cells in the C column.

How can I get it only to take into consideration the non blank cells in the C column instead of all of the cells? (knowing that I do now want to specify everytime C#:C###)...

Any tips..?