# Changing average

1. ## Changing average

Hi,
I have a quite stupid problm but I don't know how to solve it quickly.
I have to calculate the weekly average for all the weeks of an year ( 52-53 weeks 9 and I have the data in days all in a column ( A)... how should I write a quick formula to copy in all the cell , insteda that doing =average(a1:a7), average(a8;a14) and so on? Thank you very much

2. ## Re: Changing average

One way with Pivot table:
Example.xls

3. ## Re: Changing average

One downside with a pivot table is that you have to manually refresh it, although that's not necessarily a problem.

If you want formulae that automatically update, you could put down a list of your weeks and use an AVERAGEIF formula, copied down. You might find it easiest to write the conditions if you put in a helper column to calculate the week number from the date, perhaps using the WEEKNUM function.

4. ## Re: Changing average

Originally Posted by zbor
One way with Pivot table:
Attachment 89821
I Think this could be a solution. Just one question: how di you put the data in weeks in the pivot table ( 1.1.2010-7.1.2010, and so on)?
Thank you to both

5. ## Re: Changing average

right click on your data and GROUP

You can group by days, months, years or more of them

(for example only months will take average for all Aprils from 2000 to 2010, and months+years will take average of April in 2000 separate than 2001, 2002 etc)...

Just play with it slightly and you'll figure it out

6. ## Re: Changing average

Originally Posted by zbor
right click on your data and GROUP

You can group by days, months, years or more of them

(for example only months will take average for all Aprils from 2000 to 2010, and months+years will take average of April in 2000 separate than 2001, 2002 etc)...

Just play with it slightly and you'll figure it out
Amazing!!!! Thank you so much!!!!

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