A train has been delayed by a fallen tree. The train driver can see the extent of the damage and estimates the probability that the tree will be removed and the train will be able to continue its journey within the next hour is 90%. This information is communicated to other rail employees at train stations that may be affected by delays. What method has been used to assign a probability to the train delay? Use the aforementioned context to write a short paragraph that reflects on occasions when this method may be appropriate relative to other methods of assigning probability.