LibreOffice Calc: How to Calculate Average Over The Next n Rows?

[Pantona]

I have data with time stamps in the following scheme:

Column A                       Column B
21/08/2025 14:30:00.000        1.000
21/08/2025 14:30:00.100        2.004
21/08/2025 14:30:00.200        1.045
21/08/2025 14:30:00.300        1.003
21/08/2025 14:30:00.400        1.002
21/08/2025 14:30:00.500        2.001

Column A contains the time stamps, column B contains the corresponding measurement values. The dataset consists of several thousand values in the interval of 100 milliseconds.

I would like to recalculate those millisecond interval values into one second average values.

Is there a function available where I can calculate all the average values in column C without any empty rows in between?

Means: Cell C1 will show the result of AVERAGE(B1:B10), cell C2 will show the result of AVERAGE(B11:B20), and so on?

I could drag and drop the C column until the end of my data then.

[robleyd]

In C1, place your formula =AVERAGE(B1:B10) and drag down; you’ll find the formula adjusts for each cell.
Misread the question.

[karolus]

@robleyd

you’ll find the formula adjusts for each cell.

not exactly to the wishes of OP:

=AVERAGE(B1:B10)
=AVERAGE(B11:B20)

Assuming your Data starts on Row2:

C2 ⇒ =AVERAGE(OFFSET($B$2;ROW(B1)*10-10;0;10;1))	
#or
C2 ⇒ =AVERAGE(INDEX(B$2:B$2000;ROW(B1)*10-9):INDEX(B$2:B$2000;ROW(B1)*10))

a more robust Solution would be a Pivottable grouped by (seconds , minutes, hours, …)
ask-126731-pivot.ods (24.8 KB)