a rolling average question, need solution.
I am trying to get an average in a single column but cannot find any help here. All the suggestions I have found the formula errors out. I want to have this average automatically adjust to the last 12 fields that have been entered. Lets say at b1 I want the total of the last 12 fields in B. If it stats from b4 to b16 but when I add b17, b18, b19, and so on it will look at only the last 12. So when I get to b20, it is going to look at field b8 to b20 and average it.