From: Tommy on 18 May 2010 15:35 Can someone explain mathematically why the difference of the sum of the average of row two and three (Range D2:D3) as shown in cell E3 is different than the average of each individual difference in range A4:C4 as shown in cell E4. It is not obvious to me. test 1 test 2 test 3 Average Diff 10 5 10 8,33 6 1 2 3 -64,00 % -40,00 % -80,00 % -80,00 % -66,67 % -- Regards Tommy From: Reeza on 18 May 2010 15:47 On May 18, 12:35 pm, Tommy wrote:> Can someone explain mathematically why the difference of the sum of the > average of row two and three (Range D2:D3) as shown in cell E3 is different > than the average of each individual difference in range A4:C4 as shown in > cell E4. > It is not obvious to me. > > test 1  test 2  test 3  Average Diff > 10      5       10      8,33     > 6       1       2       3       -64,00 % > -40,00 %        -80,00 %        -80,00 %                -66,67 % > > -- > Regards > Tommy Weighted Average vs Average Test 2 is 5 not 10 like the others, but in percentage points they all become the same scale or same weights. Change Test 2 to 10 and 2 and you should get the same numbers or calculate a weighted average rather than average...depends on what you're looking for at the end of the day. HTH, Reeza  |  Pages: 1 Prev: Can't Save personal.xls When HiddenNext: Add-In Launch