Joint and Marginal Probability Tables
I own three fuel terminals. one in the north, one in the south and one in the mid-west. My north terminal house 25% of my employees, my south terminal house 40% of my employees and my mid-west house 35% of my employees. 10% of my north employees failed a management test, 15% of my south and 5% of my mid-west.

Using excel I'm trying to create a probability tree showing all marginal, conditional and joint probabilities. Im also trying to develop a joint probability table and determine the probability that an employee selected at random would fail the management test.