Illustration 9. (b) Ten per cent of the tools produced in a certain manufacturing process turn out to be defective. Find the probability that in a sample of 10 tools chosen at random, exactly two will...

Extracted text: Illustration 9. (b) Ten per cent of the tools produced in a certain manufacturing process turn out to be defective. Find the probability that in a sample of 10 tools chosen at random, exactly two will be defective by using (a) the binomial distribution, and (b) the Poisson approximation to the binomial distribution.