SOLUTION: I have a question about part b). A goalkeeper catches 30% of all penalty kicks against his team. a) What is the probability that out of 5 penalty kicks he catches 2? ***For

Algebra ->  Finance -> SOLUTION: I have a question about part b). A goalkeeper catches 30% of all penalty kicks against his team. a) What is the probability that out of 5 penalty kicks he catches 2? ***For      Log On


   

Question 1130144: I have a question about part b).
A goalkeeper catches 30% of all penalty kicks against his team.
a) What is the probability that out of 5 penalty kicks he catches 2?
***For this I found a solution of 0.3087.***
b) What is the probabiity that out of 5 penalty kicks he catches at least 2?
***I cannot figure out how to solve this. I feel like it's probably easy, but the at least part is throwing me off I think.
Thank you!
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
(a)  P(2) = C%5B5%5D%5E2%2A0.3%5E2%2A%281-0.3%29%5E3 = %28%285%2A4%29%2F%281%2A2%29%29%2A0.3%5E2%2A%281-0.3%29%5E3 = 0.3087,  exactly as you got (!)



(b)  "catches at least 2" means "catches 2, or 3, or 4, or 5" 


     P = P(2) + P(3) + P(4) + P(5) = (which is  EASIER  to calculate) = 1 - P(0) - P(1)  = 1 - 0.7%5E5 - 5%2A0.3%2A0.7%5E4 = 0.4718.