
Re: say I flip a coin 100 times...
Posted:
Apr 14, 2005 1:38 PM


HERC777 wrote: > 1,000,000 other people all flip 100 coins themselves. > on average, will someone flip the same 100 long sequence > I did?
NO, dumbass.
> Here's the prototype usage for average, "expected".
The expected number of flippers who will match all 100 of your flips is less than 2^(80). That's less than 1 over a million TO THE 8th POWER.
> > how long a sequence will they match up to on average?
WHO are THEY? WHO is supposed to be matching WHOM? If you are asking how long a prefix of THEIR flips will match a prefix of YOUR flips, then the AVERAGE length of the match is LESS THAN 1 FLIP LONG. Fully HALF of them miss THE VERY FIRST FLIP and so have a matchlength of ZERO! When half of some things are 0, and a quarter of them are exactly 1, it is a lot harder for their average to get bigger than 1.
> this is nothing like, whats the average > length sequence that matches > between some fixed and some random sample.
It is EXACTLY like that, DIPSHIT: The probability of two random sequences matching, and the probability of a random sequence matching a fixed one, ARE THE *EXACT* *SAME*. Maybe this will be easiest for you to see when the length of the sequence is ONE: Suppose I take a fixed sequence of length 1: H. What is the probablity of a RANDOM sequence of length 1, 1 coin flipped 1 time randomly, matching that? 1/2, THAT'S what.
Now, suppose I flip 2 coins randomly: what is the probability of their matching each other? 1/2, THAT'S what.
Idiot.

