a) The average lifetime of a SG 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 56 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: I 5 = 1' car = 7' car 7 p6 y and then 7 pf y Decide If a new value of Lambda is required to compute the Poisson probability equality: -A.. z E p(x=1)=#1=0,1,... E(X)=/\\