find prob. of rolling exactly four 2's in five rolls of die

lily06 · Nov 28, 2006

Rolling exactly 4 two's in 5 rolls of a die

I know it is probably easy, but I am trying to get this probability stuff down!

tkhunny · Nov 28, 2006

Pr(2) = p = 1/6
Pr(Not 2) = q = 1 - 1/6 = 5/6

Expand \(\displaystyle (p+q)^{5}\) and ponder its meaning.

After that, learn how to pick out the one you want.

soroban · Nov 28, 2006

Re: find prob. of rolling exactly four 2's in five rolls of

Hello, lily06!

Rolling exactly 4 two's in 5 rolls of a die

If you are familiar with the "Independent Trials" formula or "Binomial probabilities",

. . the answer is: \(\displaystyle \:{5\choose4}\,\left(\frac{1}{6}\right)^4\,\left(\frac{5}{6}\right)\)

find prob. of rolling exactly four 2's in five rolls of die

lily06

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tkhunny

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soroban

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