Hello,

Let's say I have an array of values. In Column A, the values are identifiers that put the values in Column B into groups. The values in Column B are observations. For example:

A B
001 5
001 7
001 4
001 7
014 5
014 2
014 9
030 5
030 3
201 5
201 8
201 9
201 3
201 2

I want to perform a mathematical function on the values in Column B based on the groups they are in. For example, I want to perform a mathematical function on the group with the identifer '014' so that means excel would manipulate the values [5, 2, 9]. The thing is, I don't know what each group's identifier is and there is not a set amount of observations in each group. How do I do this? Can anybody do an example and perhaps use the mean as the mathematical function? So calculate the mean of each group?

Thanks!