Pivot Table Average Problem

[Danger Mouse]

I have a simple pivot table that is averaging 7 values representing monthly
attainment. If run a simple average formula off the values i get one figure,
the pivot table average shows a different value.

Example: the seven values could be:

2/1/2008 121.04%
3/1/2008 110.54%
4/1/2008 110.23%
5/1/2008 118.90%
6/1/2008 99.89%
7/1/2008 107.66%
8/1/2008 94.59%

The average when you apply AVG() function is 108.98

The pivot table shows the average as 109.40...can anyone tell me how that's
happening? And even weirder, the same set of data is listed on two lines...
one line shows 109.40 as the average the other line shows 109.23

I have probably two strings of hair left in my head from scratching it so
much thinking over this...I'm pretty good with Excel, but this has me
stumped....

Thanks in advance...

 

[Roger Govier]

Hi

Loading your data to a fresh workbook and creating a PT with Average gives
me an overall Average of 108.98%

There must be something else within your data, or your workbook has somehow
become corrupted.
Try copying the data to a new Workbook and re-create the PT and see if you
get the same results.

 

[Dave Peterson]

The average of averages isn't the same as summing each of the entries, then
dividing by the count.

A baseball example:

You're an excellent hitter.

For the season, you're hitting .350 (35 for 100 = 35%).
For one game, you go 4 for 4 (batted 1.000 or 100%).

Your average isn't (.350 + 1.000)/2 = .675 (67.5%)

It's 39/104 = .375 (35.7%)