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gabrielmeraz
08-21-2004, 04:51 PM
This is a probability problem:
If an ordinary coin is tossed six times, what is the probability of either all heads or all tails? The Barron's book says 1/2^5 or 1/32 but, shouldn't be 1/2^6 or 1/64 since it is six times. :idea:

DrTacoElf
08-21-2004, 04:52 PM
This is a probability problem:
If an ordinary coin is tossed six times, what is the probability of either all heads or all tails? The Barron's book says 1/2^5 or 1/32 but, shouldn't be 1/2^6 or 1/64 since it is six times. :idea:

you are correct.

EDIT: misread and/or :scared:

HBomb
08-21-2004, 05:09 PM
No, in this case, you aren't correct because the key word is "or" and is the union of their probabilities, so
P(HHHHHH) = 1/64
P(TTTTTT) = 1/64
P(HHHHHH) + P(TTTTTT) = 1/64 + 1/64 = 1/32

gabrielmeraz
08-21-2004, 08:42 PM
Thank you very much, I see what you mean, so whenever you see "or" in a probability question, most of the times it would be asking for the sum of the probabilities of two species right?

HBomb
08-22-2004, 03:27 AM
Right. Use the sum (for exclusive events).