Suppose that n balls are tossed into n bins, where each toss is independent and the ball is equally likely to end up in any bin. What is the expected number of empty bins? What is the expected number of bins with exactly one ball? For large n, the probabilty expression can be simplified with a term having the base of natural logarithm, e. (hint: try to find the probability that, some bin, say j is empty (or have exactly one ball))