a). If possible, find the probability distribution function of a binomial distribution with mean 4 and variance 4/3. [3M] b). The life of a certain kind of electronic device has a mean of 250 hours and a standard deviation of 20 hours. Assuming that he distribution of h times which are measured to the nearest hour can be approximated closely with a normal curve, (i) Find the probability that any one of these devices will have a lifetime of more than 200 hours. [3M] (ii) What percentage will have life time from 250 to 300 hours