Chapter 20, Problem 20PS

1n Problem 20.12, a vendor at a baseball stadium is deciding whether to sell ice cream or soft drinks at today’s game. Prior to making her decision, she decides to listen to the local weather forecast. 1n the past. when it has been cool. the weather reporter has forecast cool weather $80\%$ of the time. When it has been warm. the weather reporter has forecast warm weather $70\%$ of the time. The local weather forecast is for cool weather.

a. Revise the prior probabilities now that you know that the weather forecast is for cool weather.

b. Use these revised probabilities to repeat Problem 20.12.

c. Compare the results in (b) to those in Problem 20.12.