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Home Q & A Board Science-Related Homework Help Mathematics
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drw1323 drw1323
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8 years ago
Please help attached is the question.
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8 years ago
bio_man: You need to type out the *whole* question
Similar Question
A committee of 3 members is selected from a club made up of 9 junior members and 21 senior members.What is the expected number of juniors in the committee?

Q: What is the expected number of juniors?

x: 0 1 2 3

P(x):

P(x = 0) = 21c3/30c3 = 19/58
P(x = 1) = 9c1*21c2/30c3 = 27/58
P(x = 2) = 9c2*21c1/30c3 = 27/145
P(x = 3) = 9c3*21c0/30c3 = 3/145

E(x) = 0*(19/58)+ 1*(27/58)+2*(27/145)+ 3*(3/145)
= 0.9

Let me know if you need another example...
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