5 In a large region of derelict land, bricks are found scattered in the earth.
- State two conditions needed for the number of bricks per cubic metre to be modelled by a Poisson distribution.
Assume now that the number of bricks in 1 cubic metre of earth can be modelled by the distribution Po(3).
- Find the probability that the number of bricks in 4 cubic metres of earth is between 8 and 14 inclusive.
- Find the size of the largest volume of earth for which the probability that no bricks are found is at least 0.4.