function: average? please help!

i'l add little part of this excel file, if anybody is willing to download and try on any kind of function

Highlight your selected data, then go to Data > Subtotals. Under "Use function" select "average", under "At each change in" select "Date", check "Add subtotal to:" for "TOC", and check off "summary below data".

DonkeyOte, can you explain me more? What is PT?

Hi,

PT is a Pivot Table
select a cell in your list
Go to Data - Pivot Tables
Follow the wizard putting date as row fields and TOC as data Field
Next right click in data Field
Select Field Setting
Change the function to " average"

BTW your attachments is an xlsx file but you use XL2003??

try this!

I added a pivot table

thanks you all. It helped me a lot..
but now i have another problem ater solving this one:
A-column i have all the dates from the calender since 1992
B column - precipitation for every day.
then the data i just made the averages of
C column - date for TOC
D column - TOC average of the dates that i just figured out with your help
i add xlsx as well...

and now i need to calculate the SUM of precipitation for each "date for TOC". and the SUM of precipitation has to be 10 days before the "date for TOC"
for example:
1st data for TOC is taken 1992-02-05. then the sumof precipitation has to be from 1992-01-27 till 1992-02-05.

You think it's possible?

PS! Yes i actually use excel2007, when i registered, i didnt recognise to change it, and now "my account" here in the forum doesnt open..