I have column A (timeline) and column B (corresponding heart frequency data).

We enter timepoint 1 into a cell (beginning of the measurement - entered into E1) and timepoint 2 (end of the measured period) into E2. I'd like to know the average heart rate for that given period and the STDEV of the heart rate data.

In E 3 we calculate the corresponding average of the heart rates :

[FONT="][/FONT]=AVERAGEIFS(B2:B10000,A2:A10000,">="&E1,A2:A10000,"<="&E2)

I don't know how to calculate the corresponding standard deviations of the above data.

I would be very grateful for help, it is to make my students' work less easier in a psychology project.

thank you!