Question

If X follows a B.D. with parameter $n=6$. If $4P(X=4)=P(X=2)$ then P equals

• A. $\frac{1}{6}$
• B. $\frac{1}{4}$
• C. $\frac{1}{8}$
• D. $\frac{1}{3}$

Answer 1

Answer: (D)

$\frac{1}{3}$

Given, $4.P(X=4)=P(X=2)$
$\Rightarrow 4{.}^6{C}_4{p}^4{q}^2{=}^6{C}_2{p}^2{q}^4$
$\Rightarrow 4p^2=q^2=(1-p{)}^2$
$\Rightarrow 3p^2+2p-1=0$ $\Rightarrow p=1/3$