Originally Posted by
pumbaa213 The variable X has a binomial distribution with n=20 and probability of success p, where p<0.1.
(i) write down an expression, in terms of p, for P(X=2).
(ii) show that p=0.05, correct to 2 decimal places if given that P(X>=1) [x is larger or equals to 1)=0.641541
Im having problems with part (ii)
This is my attempt at it: If its rubbish, just ignore it! x.x
P(X>=1) = 0.641541
P(X>=1) can be written as 1-P(X=0)
Hence,
1-P(X=0) =0.641541
Given that n=20
20C0 x p^0 x (1-p)^20 = 0.641541
1 x (1-p)^20 = 0.641541
p^20=0.641541