POISSON DISTRIBUTION:Is a ‘discrete probability distribution’ that expresses the ‘probability of a number of events occurring in a fixed period of time’ (if these events occur with a known average rate and independently of the time since the last event) It can also be used for the number of events in other specified intervals such as distance, area or volume Is generally used to model the number of events occurring within a given time interval Is a discrete distribution which takes on the values X = 0, 1, 2, 3,….In the given question, one has to study the daily admission of head injury patients in a trauma care centre, Since, it describes the no. of events in time (no. of head injury patients admitted per day, Therefore, it is a Poisson distribution.