19. A high school soccer team has two goalies. Goalie A makes the save 80% of the time. Goalie B makes the save 75% of the time. If goalie A plays 35 of the games and goalie B plays 25 of the games then:

a) Determine the probability that a save has been made by either goalie A or goalie B.

b) If a save has been made, what is the probability that is was goalie A?

c) If a goal was let in, what is the probability it was goalie B?

1 answer

(a) (35/60)*0.8 + (25/60)*0.75 = 0.779

(b) Assume N shots on goal per game, and 60 total games. Probability of save by A
= (0.8)*N*35/[0.8*N*35 + 0.75*N*25]
= 28/(28 + 18.75) = 0.599

(c) Your turn