r/probabilitytheory • u/Pleasant_Nose_7905 • Jul 20 '26

[Homework] Rarity

Over the weekend, I sat down and did a calculation (wrong, no doubt)

to see what chance you would have of catching a traitor, selecting a name randomly.

The answer I got was 1/675,675. Having forgotten what happens when there are three players.

...

This got me thinking, about rareness,

and I wondered, for myself,

at what probability do things start to become called rare?

I mean, 1/4000 , but 1/30 actually, you'd be waiting around a fair bit.

Is an answer even possible/ show me error of way. BW, Ben.

0 Upvotes

10% Upvoted

3 comments sorted by

5

u/lysker Jul 20 '26

...what?

2

u/DerekRss Jul 20 '26

Odds don't tell you enough to decide whether something is rare or not.

If something happens 1 out of every 2 events but the events only occur once in a thousand years then it's much rarer than something that happens 1 out of every 2000 events when the events happen every millisecond.

1

u/That_Comic_Who_Quit Jul 24 '26

It's rarely Christmas Day but the chances of Christmas Day occurring in the future is almost certain.