For the same reason "all the best schools are small" but aren't really [1]. It's the "Law of small numbers" that is: scale-dependency of variance. It's much e

For the same reason "all the best schools are small" but aren't really [1]. It's the "Law of small numbers" that is: scale-dependency of variance. It's much easier to get an large variance if you sample in small sets. [1] https://marginalrevolution.com/marginalrevolution/2010/09/the-small-schools-myth.html https://marginalrevolution.com/marginalrevolution/2010/09/th...