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# probabilities watch

1. Hi, i have a query that i have been given from my work that i cant seem to get anywhere with, and was wondering if anyone here can help me out. Any help will be appreciated.

In a pipe, there are a certain amount of fixings. for example 200 fixings. If 20 of the fixings are taken out and 10 are found to be faulty, what is the probability that more fixings out of the 200 are faulty? i need a general solution to this problem as going to write a program to calculate this.

Also is there any way to find the probability of where the faulty fixings are likely to be? and also what is the most efficient number of fixings to remove to test if they are faulty, where about's on the pipe should they be taken from?

thanks
2. As far as I can see, if you take a sample of 20 and 10 are faulty, the best estimate of the mean number of faulty fixings is 0.5.

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Updated: January 26, 2010
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