3 The number of incidents of radio interference per hour experienced by a certain listener is modelled by a random variable with distribution \(\operatorname { Po } ( 0.42 )\).
- Find the probability that the number of incidents of interference in one randomly chosen hour is
(a) 0 ,
(b) exactly 1 . - Find the probability that the number of incidents in a randomly chosen 5-hour period is greater than 3.
- One hundred hours of listening are monitored and the numbers of 1 -hour periods in which 0,1 , \(2 , \ldots\) incidents of interference are experienced are noted. A bar chart is drawn to represent the results. Without any further calculations, sketch the shape that you would expect for the bar chart. (There is no need to use an exact numerical scale on the frequency axis.)