SOLUTION: * A lot of 75 washers contains five in which the variability in thickness around the circumference of the washer is unacceptable. A sample of 10 washers is selected at random, with

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Question 376507: * A lot of 75 washers contains five in which the variability in thickness around the circumference of the washer is unacceptable. A sample of 10 washers is selected at random, without replacement.
i) What is the probability that at least one unacceptable washer is in the sample?
ii) What is the probability that at most one unacceptable washer is in the sample?

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
This is a hypergeometric distrribution.
i)
1-(70C10/75C10)
=1-.4786
=0.5214
.
ii)
(70C10 + (70C9 * 5C1))/75C10
=.8708
.
Ed