Suppose that you work for a newly restructured automotive company with nearly 100,000 employees. You are in charge of purchasing engines from an overseas supplier. Company policy is that you purchase several hundred engines each month to be placed into cars on the assembly line.
Your overseas supplier of engines guarantees that 10% of the new engines shipped to you will have minor oil leaks that will require a slight modification before assembly. To check out the most recent monthly shipment of the engines, you randomly select and test 200 of these engines. What is the average number of leaky engines you would expect to get.