A man was able to complete 5 files a day on an average. Let X be the number of files accomplished be this person in the next day, a) What is the appropriate probability distribution to model X? (5) b) Find the expectation and standard deviation of X. (10) c) Using (a), find P(X=2). (5) d) Find the probability that he can complete at least 4 files the next day.(5)