Question 356433
 There are 7 boys and 3 girls. If we randomly select 5 kids
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Binomial problems with n = 5, p(boy) = 0.7, and P(girl) = 0.3
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what is the probability that all 3 girls will be picked?
# of ways to pick 3 girls and 2 boys = 1*7C2 = 21
# of ways to pick 5 kids randomly: 10C5 = 252
P(3 g and 2 b's) = 21/252 = 0.08333
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What is the probability that none of the girls will be picked?
P(o g and 5 b's) = 7C5/10C5 = 0.083333
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What is the probability of 2 girls getting picked
P(2 g's and 3 b's) = 3C2(0.3)^2(0.7)^3 = 0.0926
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Cheers,
Stan H.