I have a large data set that has approximately 500 different groups with 30 weeks of data by week for each group (week is a column). There are 3 different "source" categories that each group would fall into. I would like to create a new column that would have the average value by week and source so that I can compare the actual value to the average value of that week and source category.
I have tried this in Formula Editor using the Col Mean function but cannot get it to work. Can anyone help me with this?