Question 563780: 45% of adults say cashwes are they favorite kind of nut. you randonly selectec 12 adults and ask each to name his or her favorite nut. Find the probability that the number who say cashews are their favorite nut is A exactly 3, B at least 4 and C at most 2.
Answer by ad_alta(240)   (Show Source):
You can put this solution on YOUR website! You need to use the binomial formula. For A, the probability is (12!)/[(3!)(12-3)!](.45)^3(.55)^9=0.09233.
For B, calculate the probability of 4 or more via addition (i.e. P(4)+...+P(12)) using the same formula as in A. The work for the latter would be (12!)/[(4!)(12-4)!](.45)^4(.55)^8+...+(12!)/[(12!)(12-12)!](.45)^12(.55)^0=0.865532.
Similarly, C should come to about 0.042142. Check those numbers yourself, since it's very easy to make typing errors on a calculator with so many numbers involved.
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