document.write( "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). \n" ); document.write( "

Algebra.Com's Answer #397803 by reviewermath(1029) $\"\"$ $\"About$

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If X~Binomial(n,p) then mean of X = np and Variance of X = npq where q = 1-p.
\n" ); document.write( "Therefore, np = 3 and npq = 1.2
\n" ); document.write( " $\"npq%2Fnp+=+1.2%2F3\"$
\n" ); document.write( " $\"q+=+0.4\"$
\n" ); document.write( " $\"1-p+=+0.4\"$
\n" ); document.write( " $\"highlight%28p+=+0.6%29\"$
\n" ); document.write( " $\"np+=+0.6n+=+3\"$
\n" ); document.write( " $\"highlight%28n+=+5%29\"$
\n" ); document.write( "

\n" ); document.write( " $\"highlight%28P%28X%3C4%29+=+0.663%29\"$ \n" ); document.write( "

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