basic probability
Kev hosts a TV programme and during the show he picks members of a large audience at random and asks them their star sign.
(There are 12 star signs and you may assume that the probabilities that a randomly chosen person will be born under each sign is equal)
iii)Calculate the probability that the first five people picked were all born under different signs (answer 0.382)
iv)What is the probability that at least two of the first five people picked were born under the same sign? (answer 0.618)
I understand part iii) to do part iv) you are meant to do 1- your answer to iii) which gives0.618. However in doing this you are giving the probability of the first five people having ALL THE SAME star sign...but the questions asks for atleast two.
^ I know this is trivial but please can someone tell me why the probability of them all having the same star sign is the same as the probability of atleast two having the same star sign
(There are 12 star signs and you may assume that the probabilities that a randomly chosen person will be born under each sign is equal)
iii)Calculate the probability that the first five people picked were all born under different signs (answer 0.382)
iv)What is the probability that at least two of the first five people picked were born under the same sign? (answer 0.618)
I understand part iii) to do part iv) you are meant to do 1- your answer to iii) which gives0.618. However in doing this you are giving the probability of the first five people having ALL THE SAME star sign...but the questions asks for atleast two.
^ I know this is trivial but please can someone tell me why the probability of them all having the same star sign is the same as the probability of atleast two having the same star sign
Original post by CasualSoul
X
The inverse of the probability that no two of them were born under the same sign gives the probability that at least two share a birth sign. It doesn't imply that they all do.
oh right..you summarised that wonderfully thanks!
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