Stenographer's typos. A very skilled court stenographer makes one typographical error (typo) per hour on average.
(a) What probability distribution is most appropriate for calculating the probability of a given number of typos this stenographer makes in an hour?
(b) What are the mean and the standard deviation of the number of typos this stenographer makes?
(c) Would it be considered unusual if this stenographer made 4 typos in a given hour?
(d) Calculate the probability that this stenographer makes at most 2 typos in a given hour.