(a) In 1986, the US Space Shuttle Challenger tragically exploded in flight. This accident was caused by the catastrophic failure of rubber 'O-ring' seals that linked segments of the rocket boosters together. There were six O-ring seals in Challenger (and all other Space Shuttles at the time). Table 1 shows the numbers of O-ring seal failures that had occurred on each of 23 previous Space Shuttle flights. Table 1 Number of O-ring seal failures Number of failed O-rings 0 Number of flights 16 1 2 3 456 2 0000 (i) Let p be the probability that an O-ring seal fails on a flight. What distribution is appropriate to describe the failure or non-failure of a particular O-ring seal on a particular flight? (Ensure that you define the corresponding random variable appropriately.) (ii) ~ A reasonable estimate of p is 3/46 ≈ 0.065. Explain where this number comes from. (iii) It is suggested that an appropriate model for the number of O-ring seals that fail on a particular flight might be a binomial distribution B(6, p). What assumptions are made by using this model? In your opinion, is a binomial model appropriate? Briefly justify your answer