Average the sum of rows without a creating new column in Excel

Question

Here\'s a sample of my matrix:

A   B   C   D   E
1   0   0   1   1
0   0   0   0   0

0   0   1   1   0
0   2           1

You can think of eac

Answer 1

You can do this more concisely with an array formula, but the short answer to fix up your existing formula is, if you have a blank cell in your sheet somewhere (say it's F1) AVERAGE will ignore blank cells so change your formula to

=AVERAGE(IF(AND(A1<>"",B1<>"",C1<>"",D1<>"",E1<>""),SUM(A1:E1),F1),IF(AND(A2<>"",B2<>"",C2<>"",D2<>"",E2<>""),SUM(A2:E2),F1),IF(AND(A3<>"",B3<>"",C3<>"",D3<>"",E3<>""),SUM(A3:E3),F1),IF(AND(A4<>"",B4<>"",C4<>"",D4<>"",E4<>""),SUM(A4:E4),F1),IF(AND(A5<>"",B5<>"",C5<>"",D5<>"",E5<>""),SUM(A5:E5),F1))

This would be one array formula version of your formula - it uses OFFSET to pull out each row of the matrix then SUBTOTAL to see if every cell in that row has a number in it. Then it uses SUBTOTAL again to work out the sum of each row and AVERAGE to get the average of rows.

=AVERAGE(IF(SUBTOTAL(2,OFFSET(A1,ROW(A1:A5)-ROW(A1),0,1,COLUMNS(A1:E1)))=COLUMNS(A1:E1),SUBTOTAL(9,OFFSET(A1,ROW(A1:A5)-ROW(A1),0,1,COLUMNS(A1:E1))),""))

Has to be entered as an array formula using CtrlShiftEnter

Note 1 - some people don't like using OFFSET because it is volatile - you can use matrix multiplication instead but it's arguably less easy to understand.

Note 2 - I used "" instead of referring to an empty cell. Interesting that the non-array formula needed an actual blank cell but the array formula needed an empty string.

You can omit the empty string

=AVERAGE(IF(SUBTOTAL(2,OFFSET(A1,ROW(A1:A5)-ROW(A1),0,1,COLUMNS(A1:E1)))=COLUMNS(A1:E1),SUBTOTAL(9,OFFSET(A1,ROW(A1:A5)-ROW(A1),0,1,COLUMNS(A1:E1)))))