Rolling date looking 30 Days past
 

I'm logging data into a spreadsheet daily and keeping track of a rolling 30
days average and 1 std dev above the average. How do I easily create a way
to update this everyday without changing the formula every day? I have dates
on the left and numbers (25, 32, 28, etc.) next to the date. Thanks.

Rolling date looking 30 Days past
 

If you have headers and data starts from row 2 ; in row 31 insert the formula
and copy down as required...In the below example it average the values of Col
B

=AVERAGE(INDIRECT(ADDRESS(ROW()-29,1) & ":B" & ROW(B31) ))

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---------------
Jacob Skaria


"Chris" wrote:

I'm logging data into a spreadsheet daily and keeping track of a rolling 30
days average and 1 std dev above the average. How do I easily create a way
to update this everyday without changing the formula every day? I have dates
on the left and numbers (25, 32, 28, etc.) next to the date. Thanks.

Rolling date looking 30 Days past
 

Another interp ...
Assume real dates in A1 down, corresponding values in B1 down
In C1: =AVERAGE(OFFSET(INDIRECT("B"&MATCH(TODAY(),A:A,0)) ,,,-30))
will return the required rolling average which is dynamic to the current
date (today). It of course presumes that there's always a match found in col
A for today's date, and that there's = 30 data rows in cols A/B to start with
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"Chris" wrote:
I'm logging data into a spreadsheet daily and keeping track of a rolling 30
days average and 1 std dev above the average. How do I easily create a way
to update this everyday without changing the formula every day? I have dates
on the left and numbers (25, 32, 28, etc.) next to the date. Thanks.