pivot table % calculation error

[Lonnie]

Hey all, minor problem with my pivot table calculations. It is set up to
quality record values per each day, and formulate a percent of accuracy.
There may be several entries per day, so my chart lists average %... My
pivot table lists the dates and the averages just fine, BUT the "grand total"
figure is wrong..... the grand total is figured based off an average of all
the daily averages which is very inaccurate.

example: day 1 may have 50 units, with 48 quality units, for a quality of 96%
day 2 may have 5000 units, with 4950 quality units, for a
quality of 99%

the overall quality for this record set should be [(5050-52)/5050]=99%, but
the calculation comes out (96+99)/2= 97.5%

Is there any way at all to reconfigure how this pivot table calculates the
grand total?
Or, do you have any other suggestions for a quick look at my overall numbers?

Thanks a millioin in advance

 

[KARL DEWEY]

Mathematically you can not average averages!

You have to use orignal numbers.

 

[Lonnie via AccessMonster.com]

right, i understand that--- but the pivot table is doing just that---it's
averaging my averages

Mathematically you can not average averages!

You have to use orignal numbers.

Hey all, minor problem with my pivot table calculations. It is set up to
quality record values per each day, and formulate a percent of accuracy.

[quoted text clipped - 15 lines]

Thanks a millioin in advance

 

[Lonnie via AccessMonster.com]

so my question is--- how do i make it stop, and make it pay attention to the
real numbers?

right, i understand that--- but the pivot table is doing just that---it's
averaging my averages

Mathematically you can not average averages!

[quoted text clipped - 5 lines]

 

[KARL DEWEY]

Someone else will need to help you as I do not know pivot tables.

so my question is--- how do i make it stop, and make it pay attention to the
real numbers?

right, i understand that--- but the pivot table is doing just that---it's
averaging my averages

Mathematically you can not average averages!

[quoted text clipped - 5 lines]

Thanks a millioin in advance