Probability Question 138
Question: The mean and variance of a random variable X having a binomial distribution are 4 and 2 respectively, then $ P(X=1) $ is
[AIEEE 2003]
Options:
A) 1/32
B) 1/16
C) 1/8
D) ¼
Show Answer
Answer:
Correct Answer: A
Solution:
$ . \begin{vmatrix} np=4 \\ npq=2 \\ \end{vmatrix} \Rightarrow q=\frac{1}{2},p=\frac{1}{2},n=8 $
$ P(X=1)={{}^{8}}C_1( \frac{1}{2} ){{( \frac{1}{2} )}^{7}} $
$ =8.\frac{1}{2^{8}}=\frac{1}{2^{5}}=\frac{1}{32} $ .
BETA
