Greg Stark wrote: >> Doesn't all that assume a normally distributed random variable?

> I don't think so because of the law of large numbers. If you have a large > population and sample it the > sample behaves like a normal distribution when if the distribution of the > population isn't. Statistics is the part of mathematics I know least of, but aren't you saying that in a large enough sample of people there will always be some with age < 0 (which is what a normal distribution would imply)? Yours, Laurenz Albe -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers