Rolling 12 month problem

[mved27]

Hi

Every quarter, I receive a single aggregate value of the spend in the last 12 months. I have 4 such aggregate values received over the previous 4 quarters.
However, this quarter, I have to find out what is the spend in the previous 3 months. Is there anyway to do this with the 4 aggregate values?

In the attached sample image with made-up numbers - I have the values in Red and using that I have to find the values in green - In the attached example the answer I want is £5.85? Is there anyway I can derive this mathematically i.e. from the 4 aggregate values can I derive the quarterly figure.

Many thanks for your time to look into this.

 

[Deleted member 4993]

Hi

Every quarter, I receive a single aggregate value of the spend in the last 12 months. I have 4 such aggregate values received over the previous 4 quarters.
However, this quarter, I have to find out what is the spend in the previous 3 months. Is there anyway to do this with the 4 aggregate values?

In the attached image - I have the values in Red and using that I have to find the values in green - I just need £5.85 as the answer.
Is there anyway I can derive this mathematically?

Many thanks for your time to look into this.

I am not sure exactly what is needed here.

You do see that if you add the numbers in green - the sum is 5.85.

 

[mved27]

I am not sure exactly what is needed here.

You do see that if you add the numbers in green - the sum is 5.85.

Hi - I 've updated the problem. The £5.85 is just an illustration. In the illustration, if I just have the aggregate values (in Red), can I find the quarterly value (in Green). The spend in the previous 12 months can be completely Random.

 

[JeffM]

Like Subhotosh Khan, I am not sure I understand the problem.

If I do understand it, the answer is "No, you can't." All you can tell from the successive figures in red is the difference between the twelve-month totals, but there are two changes in that number. One relates to the three months where old data are dropped, and the other to the three months where new data are added. You cannot disentangle the combined effect of the two changes from a single difference. Make sense?