a) The average lifetime of a 5G Mobile telephone is 7 years. Suppose that the lifetime follows an exponential distribution. (Hint: use the relationship between the Exponential and Poisson distributions) (iii) If a consumer immediately replaces a 5G Mobile telephone once it has ceased to work, what is the probability that they need to replace the telephone twice in a period of 5 years? Initially: = = per year 5 and then An = = per year Decide if a new value of Lambda is required to compute the Poisson probability equality: P (X = x) = - e- An (An ) " x = 0, 1, . . . E(X) = >n