Consider writing onto a computer disk and then sending it through a certifier that counts the number of missing pulses. suppose this number x has a poisson distribution with parameter μ = .2. (suggested in "average sample number for semi-curtailed sampling using the poisson distribution," j. quality technology, 1983: 126–129.)

a. what is the probability that a disk has exactly one missing pulse?
b. what is the probability that a disk has at least two missing pulses?
c. if two disks are independently selected, what is the probability that neither contains a missing pulse?