Mabye I should read that book. Why the hell should you change? You’re chances that you chose the big prize are the same as they were before you were shown the no-big prize behind the other non-chosen door.
The maffs ain’t behind you. : )
Logic is not logical.
Read it - it’s a beautiful piece of writing.
It’s simple if you know how…
Consider the discrete random variables:
C belongs in the set {1, 2, 3}: the number of the door hiding the prize,
S belongs in the set {1, 2, 3}: the number of the door Selected by the player, and
H belongs in the set {1, 2, 3}: the number of the door opened by the Host.
As the host’s placement of the prize is random, all values of C are equally likely. The initial (unconditional) probability of C is then
P(C) = 1/3 , for every value of C.
Further, as the initial choice of the player is independent of the placement of the prize, variables C and S are independent. Hence the conditional probability of C given S is
P(C|S)= P(C), for every value of C and S.
The host’s behavior is reflected by the values of the conditional probability of H given C and S:
P(H | C, S) = 0 if H = S, (the host cannot open the door picked by the player)
P(H | C, S) = 0 if H = C, (the host cannot open a door with the prize behind it)
P(H | C, S) = 1/2 if S = C, (the two doors with no prize are equally likely to be opened)
P(H | C, S) = 1 if H <> C and S <> C, (there is only one door available to open)
The player can then use Bayes’ rule to compute the probability of finding the prize behind any door, after the initial selection and the host’s opening of one. This is the conditional probability of C given H and S:
P(C|H, S)=[P(H|C, S)*P(C|S)] / P(H|S)
where the denominator is computed as the marginal probability
P(H|S)= sum_{C=1 to 3}: P(H,C|S)
= sum_{C=1 to 3}: P(H|C,S)* P(C|S)
Thus, if the player initially selects Door 1, and the host opens Door 3, the probability of winning by switching is
P(C=2|S=1,H=3) = (1*1/3)/(1/2*1/3 + 1*1/3 + 0*1/3) = 2/3If you have 30 people in a room, you better have it well-ventilated.
variety is the nectar of life.
More than 50%. It is an old con man’s way of making good money in that it is mostly a sure fire win of a bet.
More than 50% is pretty good, but more than half is better.
[quote=“Edgar Allen”]
so 30/366 gives about 12% for any given date[/quote]
30/366 = 0.082, why so in getting 12% ?
[quote=“It is me again”][quote=“Edgar Allen”]
so 30/366 gives about 12% for any given date[/quote]
30/366 = 0.082, why so in getting 12% ?[/quote]
Pah round it - up your is 10%, down my is 10% - same same but different
I was wrong anyway so put your calculator away Popeye.
It would all fuck up if you were born on Feb 29th.
Lies, damn lies and statistics.
Depends. If it’s me and 29 glamour models…
As to the birthday question… 
All I can say is that in 35 years I have only ever met one person who shared mybirthday, and oddly enough, it was the same day and year! FWIW, it was a guy I went to school with and he was a total ass, so seeing as I’m sublime in all ways I’d say there’s a 50% chance of two people born on the same day and year being awesome. There’s only so much awesomeness to go around. 