Math Question

[gabrielmeraz]

Advertisement - Members don't see this ad

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.

 

[DrTacoElf]

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.

you are correct.

EDIT: misread and/or

 

[HBomb]

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]

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]

Right. Use the sum (for exclusive events).