Total average in PBI table is not correct

[MarcinSV]

Hi,

I don't understand why average in total is not correct, using standard table in powerbi.
In rows values are group by customers correctly (as average):
Customer A | 17,44
Customer B | 4,09
Customer C | 3,30
Customer D | 2,93
Customer E | 2,91
Customer F | 2,58
Customer G | 2,47

TOTAL: 4,07 -> not correct, should be average = 5,10

[Anonymous · Accepted solution]

This is the expected behaviour. The total average will not take an average of the averages per customer. The total average will take an average from the original data.

[MarcinSV]

Of course!!! I was trying to calculate average from average 🙂

And its a difference like in example:

select (1+2) / 2. = 1.5

select (1+2+3) / 3. = 2

select (1.5 + 2) / 2 = 1.75 -> AVG from AVG

select (1+2+1+2+3) / 5. = 1.8 -> correct AVG

Thank's for help in showing the way 🙂

[Anonymous]

Hello,

do you find the solution? 

I have the same problem.

I don't know how to calculate average of averages.

Thanks in advance.

[MarcinSV]

Calculating average from average its not a good idea because:

select (1+2) / 2. = 1.5 -> this is average

select (1+2+3) / 3. = 2 -> this is average

then if you calculate avg from avge you have:  select (1.5 + 2) / 2 = 1.75 -> AVG from AVG
but proper calculate is: select (1+2+1+2+3) / 5. = 1.8 -> correct AVG

So it's not an error of PBI but mistake in calculating average from average (1.75 vs 1.8 on above example).