calculating a weighted average using formula
 

I have data from a series of studies in 2 columns of data (G1-G15) &
(H1-H15).

Column 1 = the number positive for an event in each study
Column 2 = the sample size for each study

I calculated a sum for column 1 & column 2 in G16 & H16 respectively.
In addition I want to calculate the average and standard deviation.


The following formula computes an average but I also need the
standard deviation.

=G16*100/H16

Any assistance is appreciated.

Bob

Hi Bob,

I guess for Standard Deviation you could use the function STDEV()

I usually calculate the weighted average using the following formula:

=SUMPRODUCT(G1:G15,H1:H15)/SUM(H1:H15)

in your case could also be:

=SUMPRODUCT(G1:G15,H1:H15)/H16

Regards,
KL


"bob green" wrote in message
. ..

I have data from a series of studies in 2 columns of data (G1-G15) &
(H1-H15).

Column 1 = the number positive for an event in each study
Column 2 = the sample size for each study

I calculated a sum for column 1 & column 2 in G16 & H16 respectively.
In addition I want to calculate the average and standard deviation.


The following formula computes an average but I also need the
standard deviation.

=G16*100/H16

Any assistance is appreciated.

Bob