p=80% (chance of winning a game)

n=5 (number of games)

What is the probability that you will win at least 4 games (find the probability that x is greater than or equal to 4).

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- Nov 7th 2008, 04:51 AMJohhnySDProbabilty Question
p=80% (chance of winning a game)

n=5 (number of games)

What is the probability that you will win at least 4 games (find the probability that x is greater than or equal to 4). - Nov 7th 2008, 05:26 AMSoroban
Hello, JohhnySD!

This is a Binomial probability.

Quote:

p = 80% (chance of winning a game)

n = 5 (number of games)

What is the probability that you will win at least 4 games?

"Win at least 4 games" means "Win 4 games or Win 5 games."

. . $\displaystyle P(x\!=\!4) \;=\;{5\choose4}(0.8)^4(0.2)^1 \;=\;0.4096$

. . $\displaystyle P(x\!=\!5) \;=\;{5\choose5}(0.8)^5(0.2)^0 \;=\;0.32768$

Therefore: .$\displaystyle P(x \geq 4) \;=\;0.4096 + 0.32768 \;=\;0.73728 \;\approx\;73.7$%

- Nov 7th 2008, 05:43 AMJohhnySD
thank you so much!!

- Nov 8th 2008, 07:41 AMCaptainBlack