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easy dice problem, please quickly help me.
A fair die is rolled 200 times. What is the probability that a five or a six shows up less than 25% of the time?
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#2
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Re: easy dice problem, please quickly help me.
bump. common someone has to know the answer!
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#3
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Re: easy dice problem, please quickly help me.
The answer is a summation of the chances of N=0 to 49 times that a 5 or a 6 is rolled.
The formula for any N between 0 and 200 is F(N)=[200!/(N!*(200-N)!)](1/3)^N*(2/3)^(200-N)] So use this formula to determine F(N) for N=0 to 49 and then add them up and voila you are done. This isn't a hard problem just very tedious. |
#4
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Re: easy dice problem, please quickly help me.
[ QUOTE ]
A fair die is rolled 200 times. What is the probability that a five or a six shows up less than 25% of the time? [/ QUOTE ] Using Excel =BINOMDIST(49,200,1/3,TRUE) = 0.42%. This gives the exact answer. Or using the normal approxmimation: sigma = sqrt[200*(1/3)*(2/3)] = 6.67. 49 is 2.64 sigma below the average of 66.67, corresponding to 0.41%. |
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