Question 1

The airline industry defines an on-time flight as one that arrives within 15 minutes of its scheduled time. The following table shows the number of on-time and late flights leaving Philadelphia and arriving in Orlando during a recent time period by airline:

Airline	On-Time	Late
Frontier	239	68
US Airways	288	130
Southwest	180	63

What is the probability that a randomly selected flight on this route was on time?

1. What is the probability that a randomly selected flight was from Southwest and was on time?
2. Do Airline and on-time performance seem to be dependent or independent? Explain your reasoning.
3. What is the probability that a randomly selected flight was from Frontier or was on time?
4. Given that the flight was late, what is the probability that it was from US Airways?
5. Given that the flight was from Southwest, what is the probability that it was late?
6. Construct a probability tree for these probabilities, branch first on Airline and then arrival timeliness. Handwritten trees are acceptable as long as they are readable.