Probabilty of PT notes

[Starzinger]

Dont know if this has been discussed before, but im a little curious, how many hands do you need with someone in Pokertracker before the numbers actually means something?

And, what's the probability of someone having, say, vpip of 30 and i have him on 300 hands, that he actually is a bit on the loose side? Do you need more hands, or maybe less? Does the different notes (like aggression, etc.) require different samplesizes to make sense? You know, that kind of stuff. =)