IB Statistics and Probability Problem 008
José travels to school by bus. Each day, the probability that José misses his bus is \(\frac{1}{3}\).
If he misses his bus, the probability that he is late for school is \(\frac{7}{8}\).
If he does not miss his bus, the probability that he is late is \(\frac{3}{8}\).
Let \(E\) be the event "he misses his bus" and \(F\) the event "he is late for school".
The information above is shown in the following tree diagram.
- Find
- \(P(E \cap F)\)
- \(P(F)\)
- Find the probability that
- José misses his bus and is not late for school;
- José missed his bus, given that he is late for school.
The cost for each day José takes the bus is 3 euros. José goes to school on Monday and Tuesday.
Copy and complete this probability distribution table.
Find the expected cost over the two days for José.