SOLUTION: A large company has an inspection system for the batches of new clutches purchased from vendors. A batch typically contains 37 clutches. In the inspection system a random sample of

Algebra ->  Probability-and-statistics -> SOLUTION: A large company has an inspection system for the batches of new clutches purchased from vendors. A batch typically contains 37 clutches. In the inspection system a random sample of      Log On


   



Question 1199377: A large company has an inspection system for the batches of new clutches purchased from vendors. A batch typically contains 37 clutches. In the inspection system a random sample of 19 is selected and all are tested. Suppose that there are 11 faulty clutches in the batch of 37. What is the probability that for a given sample there will be 6 faulty clutches?

Answer by ikleyn(52790) About Me  (Show Source):
You can put this solution on YOUR website!
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A large company has an inspection system for the batches of new clutches purchased
from vendors. A batch typically contains 37 clutches. In the inspection system
a random sample of 19 highlight%28clutches%29 is selected and all are tested.
Suppose that there are 11 faulty clutches in the batch of 37 highlight%28clutches%29.
What is the probability that for a given sample there will be highlight%28exactly%29 6 faulty clutches?
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            I edited your post to make its meaning absolutely clear and unambigous.


The probability in this problem is a ratio, whose denominator is the number of combinations
of 37 clutches taken 19 at a time

    C%5B37%5D%5E19 = 17672631900.

To calculate this great number, I used standard Excel function COMBIN(N,n).
It makes calculations faster than I can blink my eyes.



The numerator is  the number of all possible 19-tuples of clutches, containing 6 of 11 faulty clutches.

These special 19-tuples are of the form (6 of 11 faulty clutches, 19-6=13 of 37-11=26 good clutches), and their number is


    C%5B11%5D%5E6%2AC%5B37-11%5D%5E%2819-6%29 = C%5B11%5D%5E6%2AC%5B26%5D%5E13 = 462*10400600 = 4805077200.



Again, the number of combinations in this formula I calculated using Excel function COMBIN.



Thus the final probability is  P = 4805077200%2F17672631900 = 0.2719  (rounded).    ANSWER

Solved.