Knowing the diameter values for +/- one standard deviation is only going to account for 68.26% of the data...Perhaps this knowledge can help you figure out how to account for the rest of the data in the normal distribution so that you are accounting for 99.73% of the data (+/- 3 sigma). It's been so long since I've dealt with this type stuff....strange how those percentages have always stuck in my mind.....


>>Maybe std() helps (calculate and select-sql).
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>STD() calculates the Standard Deviation of a field for a group of records.
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>My problem is that I only know the diameter value for +/- one standard deviation. The only other value I know is total population count. I basically something that will start at standard deviation and work back to the raw data.
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>TC