Qi Wang, Department of Statistics
Sep 12, 2018
After the first exam, a student will go to the beach
(event B) depending on whether they pass the exam (event A).
The probability a student will pass is 0.9. If a student passes,
they go to the beach with a probability of 0.8. However,
a student who fails the exam will only go to the beach with
a probability of 0.4.