Question

If X assumes value of $10,2$ and $3$ with the probability of $0.2,0.4$ and $0.4$ respectively. What the expected value of X.

• A. $3.20$
• B. $1.8$
• C. $2.80$
• D. $4.0$

Answer 1

The correct option is D $4.0$

According to the question, the probability distribution of variable X can be written as:

X	2	3	10
P(X)	0.4	0.4	0.2

The expected value of X is nothing but the mean of X, i.e., $\mu$

Hence, $\mu =E\left(X\right)={\sum }_{i=1}^n{x}_i{p}_i$

$\mu =2\times 0.4+3\times 0.4+10\times 0.2=0.8+1.2+2=4.0$