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# binomial distribution help Watch

1. for B(10,0.22)

how would you work out P(X>=6)

really stuck, thank you
2. (Original post by raiden95)
for b(10,0.22)

how would you work out p(x>=6)

really stuck, thank you
p(x>=6) = 1- p(x<=5)
3. (Original post by joostan)
p(x>=6) = 1- p(x<=5)
but 0.22 is not in the tables
4. (Original post by raiden95)
but 0.22 is not in the tables
although this is long it does work I'm sure there's a faster method I'm missing.
5. Mean = 10 and S.D = 0.22

P ( X >= 5 ) = P ( Z >= 5-10/0.22)

therefore = P ( Z >= -0.23 )

now you need to change that (-0.23)

you do 1 - P ( Z <= 0.23) >>>0.23 in the table look for P which is 0.5910

now do 1 - 0.5910 = 0.409 is the answer !

Hope it is clear .
6. (Original post by charly2012)
Mean = 10 and S.D = 0.22

P ( X >= 5 ) = P ( Z >= 5-10/0.22)

therefore = P ( Z >= -0.23 )

now you need to change that (-0.23)

you do 1 - P ( Z <= 0.23) >>>0.23 in the table look for P which is 0.5910

now do 1 - 0.5910 = 0.409 is the answer !

Hope it is clear .
How did you come to the conclusion that mean = 10? n=10, n is not the mean. It's Binomial distribution, not normal distribution, those are binomial parameters, not normal parameters.
If a random variable X follows a binomial distribution then X~B(n,p)
7. oh my bad . i thought it was normal distribution
8. (Original post by Robbie242)
although this is long it does work I'm sure there's a faster method I'm missing.
I was thinking of this too, really was hoping there was an easier way or maybe its just a typical stupid textbook question lol thanks
9. (Original post by charly2012)
oh my bad . i thought it was normal distribution
i could actually use normal distribution by normal approximation, but since this is hypothesis testing it would take very long to test other values
10. (Original post by raiden95)
I was thinking of this too, really was hoping there was an easier way or maybe its just a typical stupid textbook question lol thanks
np and yeah its stupid, but I think this is the only route tbh, np

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