Question

One thousand sheets of aluminum alloy produced by the same manufacturer were examined for surface flaws. Assume surface flaws occur randomly and independently at a constant rate with an average of 4 flaws per sheet. Sheets are all the same size.

a) [3 points] What is the probability that a randomly chosen sheet contains more than 1 surface flaw?

b) [3 points] When 10 sheets are picked at random, what is the probability that 6 of these sheets have more than 1 surface flaw on them?

c) [4 points] Given that a sheet has more than 1 surface flaw on it, find the probability that it has exactly 10 surface flaws.

Answer 1