Question

A random variable $X$ takes the values $0,1$ and $2$. If $P(X=1)=P(X=2)$ and $P(X=0)=0.4$, then the mean value of the random variable $X$ is

• A. $0.2$
• B. $0.5$
• C. $0.7$
• D. $0.9$

Answer 1

Answer: (D)

$0.9$

$P(X=0)+P(X=1)+P(X=2)=1$
Hence, $P(X=1)=P(X=2)=(1-0.4)/2=0.3$
Mean Value $=\sum x\left(i\right)\times P\left(x\right(i\left)\right)$

Therefore, average value $=0\times 0.4+1\times 0.3+2\times 0.3=0.9$.