Exercise 2.8 (Flight delays) For a certain airline, 30% of the flights depart in the morning, 30% depart in the afternoon, and 40% depart in the evening. Frustratingly, 15% of all flights are delayed. Of the delayed flights, 40% are morning flights, 50% are afternoon flights, and 10% are evening flights. Alicia and Mine are taking separate flights to attend a conference. Mine is on a morning flight. What’s the probability that her flight will be delayed? Alicia’s flight is not delayed. What’s the probability that she’s on a morning flight? Exercise 2.14 (Late bus) Li Qiang takes the 8:30am bus to work every morning. If the bus is late, Li Qiang will be late to work. To learn about the probability that her bus will be late ( π ), Li Qiang first surveys 20 other commuters: 3 think π is 0.15, 3 think π is 0.25, 8 think π is 0.5, 3 think π is 0.75, and 3 think π is 0.85. Convert the information from the 20 surveyed commuters into a prior model for π . Li Qiang wants to update that prior model with the data she collected: in 13 days, the 8:30am bus was late 3 times. Find the posterior model for π . Compare and comment on the prior and posterior models. What did Li Qiang learn about the bus?

Logistic Regression