SOLUTION: Im so confused, I don't even know where to start! they seem like the same question..please help : (! 1.) 100 units are shipped,the probabilty that one is defective is .2, you se

Algebra ->  Probability-and-statistics -> SOLUTION: Im so confused, I don't even know where to start! they seem like the same question..please help : (! 1.) 100 units are shipped,the probabilty that one is defective is .2, you se      Log On


   



Question 271056: Im so confused, I don't even know where to start! they seem like the same question..please help : (!
1.) 100 units are shipped,the probabilty that one is defective is .2, you select 12 at random, what is the probabilty 3 are defective?
2.)A shipment has 20 bad and 80 good units, you pick 12 at random, what is the probabilty 3 are defective?

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
1.) 100 units are shipped,the probabilty that one is defective is .2, you select 12 at random, what is the probabilty 3 are defective?
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Binomial Problem: n = 12 ; p = 0.2
P(x = 3) = 12C3(0.2)^3(0.8)^9 = binompdf(12,0.2,3) = 0.2362
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2.)A shipment has 20 bad and 80 good units, you pick 12 at random, what is the probabilty 3 are defective?
P(x = 3) is same as #1.
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cheers,
Stan H.