Refer to Exercise 5.69. The company purchasing the machines returns the defective ones for repair. If it costs $50 to repair each machine, find the mean and variance of the total repair cost. In what interval would you expect the repair costs on these five machines to lie? [Hint: Use Tchebysheff's Theorem.]
Exercise 5.69
A warehouse contains 10 printing machines, 4 of which are defective. A company randomly selects five of the machines for purchase. What is the probability that all five of the machines are non-defective?