To be statistically correct, you would have first to do sufficient retries to estimate, if the standard deviation is the correct guess.
https://stats.stackexchange.com/questions/108578/what-does-standard-deviation-tell-us-in-non-normal-distribution.
This may or may not be practical depending on the system behavior (influences of other processes may make the exact distribution unobservable in practice), so it is usually skipped and Gaussean distribution assumed.
Currently it is done like this:
https://github.com/andrewrk/poop/blob/b01058a8081e5584f1c28f74c59643e413b562df/src/main.zig#L365
but maybe there is better way to do it, that is more well accepted in the field of statistics.
(perhaps std deviation should be involved?)