> I'm not sure what the ISO / ANSI standard for STDDEV is exactly, I assume you mean an API standard here, rather than definition of the statistical functions themselves? As your links into the PostgreSQL documentation indicate, there's a difference between sample standard deviation and population standard deviation. The latter then gets us into [probability density functions](https://mathworld.wolfram.com/ProbabilityDensityFunction.html) and such. Why would we put such complexity into a "lite" library for storing and retrieving data? Isn't that why we have a host programming language for SQLite? Load the numbers as a list/array, etc., and pass them to the statistics library for the host language.