#1
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Probability Question
Just bought "Probability Demystified" by Allan Bluman and I came across this problem on page 71.
A die is rolled five times. What is the probability of getting 5 twos? a. 1/8 b. 1/4 c. 1/6 d. 1/32 The answer, according to the key in the back of the book, is letter "d". Now I thought the probability of getting 1 two on a die is 1/6. The probability of getting 2 twos after rolling the die twice should be 1/36, correct? So if you rolled the dice five times, shouldn't the probability of getting ALL twos be 1/7776? What am I missing? [Please don't embarass me with any "you idiot" comments. I'm trying to understand this stuff, and I happen to have a very non-mathematical like brain.] |
#2
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Re: Probability Question
You're right. It sounds like the author was thinking of flipping a coin rather than rolling a die - the odds of getting 5 tails on 5 flips would be 1/32.
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#3
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Re: Probability Question
You are missing the fact that the die in question has half its face labled with a two. [img]/images/graemlins/smile.gif[/img]
Yeah, that has to be an author error. If you enjoy dice questions check out this thread from STT. |
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