"averaging" standard deviations


New Member

I've been given the mean and standard deviation of many sets of the same measurement (bead size). So, I basically have a list of means and a list of corresponding standard deviations. I need to pool and analyze the data to figure out the overall distribution of bead size over these 100+ sets. Fortunately, each group has the same number of measurements, so they can be weighted equally.

Ideally, I would like to create an aggregate distribution curve for all of the data, but as I only have a list of 100+ means and SDs, I'm not sure how to do this in excel. Is it possible?

If I can't easily make a size distribution curve, at the very least I would like to (1) get a total mean (I am assuming since all groups are of equal size I can average the means), and then (2) get an "average" standard deviation. I can't figure out how to get an average standard deviation. Can anyone help with this?


Ambassador to the humans
Would you care to share the solution? Others might able to learn from what you did... and who knows maybe you assumed something that isn't true and one of us can help you catch that. Either way it would be nice if you shared what you did.