I have a simple matrix. The row group is schoolname. The column group is tweek. and the data field is thours (sum(thours)). on the right side of my matrix, I want to display the Average hours for all the week columns. SSRS can do a sum very simply, but when I use the avg function, I get erroneous results. I've googled this problem and can't find an explanation that I understand. Do I somehow use the inscope function in the data field ?? I just don't know. and I don't understand how to use the inscope function

Can you provide some examples where sum works and avg doesn't?