Final answer:
The random variable is the length of time a commuter must wait for a train to arrive. The distribution of the random variable X is uniform with a range from 0 to 8 minutes.
Step-by-step explanation:
a. The random variable is the length of time a commuter must wait for a train to arrive. So, in this case, the random variable is X.
b. The distribution of the random variable X is uniform with a range from 0 to 8 minutes. We can represent this using the notation X~ U(0,8).