SOLUTION: A random variable X has a binomial probability distribution with parameters n and p. The mean value is 3 and the variance is 1.2. Find the values of n and p and hence calculate, co

Algebra ->  Probability-and-statistics -> SOLUTION: A random variable X has a binomial probability distribution with parameters n and p. The mean value is 3 and the variance is 1.2. Find the values of n and p and hence calculate, co      Log On


   

Question 631786: A random variable X has a binomial probability distribution with parameters n and p. The mean value is 3 and the variance is 1.2. Find the values of n and p and hence calculate, correct to three significant figures, P(X<4).
Answer by reviewermath(1029) About Me  (Show Source):
You can put this solution on YOUR website!
If X~Binomial(n,p) then mean of X = np and Variance of X = npq where q = 1-p.
Therefore, np = 3 and npq = 1.2
npq%2Fnp+=+1.2%2F3
q+=+0.4
1-p+=+0.4
highlight%28p+=+0.6%29
np+=+0.6n+=+3
highlight%28n+=+5%29

highlight%28P%28X%3C4%29+=+0.663%29