In the old days, there was a probability of 80% of success in
any attempt to make a telephone call. (This often depended on the
importance of the person making the call, or the operator’s
curiosity.) In six attempted calls, (a) Construct a probability
distribution for X = the number of successful calls in six
attempts. (b) Find the probability that at least two calls will be
made successfully. (c) Find the mean and standard deviation of the
distribution.