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# A die is rolled 12 times Find the probability of rolling no more than 4 twos

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A die is rolled 12 times Find the probability of rolling no more than 4 twos

Guest Apr 29, 2017
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A die is rolled 12 times Find the probability of rolling no more than 4 twos

Each roll is an independent event. So this is binomial probability.

You have to work out the prob of

0 rolls of 2

1 rolls of 2

2rolls of 2

3 rolls of 2

4 rolls of 2

add then all together and subtract the answer from 1.

P(0 rolls of 2)=  $$(\frac{5}{6})^{12}$$

P(1 rolls of 2)=  $$\binom{12}{1}(\frac{1}{6})^1(\frac{5}{6})^{11}$$

P(2rolls of 2)=  etc

P(3 rolls of 2)=

P(4 rolls of 2)=

etc

Melody  Apr 29, 2017