Find the expected value of a random variable X having the following probability distribution: $$\begin{array} { c c c c c }
x & 2 & 4 & 6 & 8 \
P ( X = x ) & \frac { 9 } { 40 } & \frac { 6 } { 40 } & \frac { 1 } { 40 } & \frac { 24 } { 40 }
\end{array}$$ Round your answer to tenth if necessary.
A) $E ( X ) = 4$
B) $E ( X ) = 5$
C) $E ( X ) = 6$
D) $E ( X ) = 10$
E) $E ( X ) = 20$

Question

Find the expected value of a random variable X having the following probability distribution: $$\begin{array} { c c c c c } 
x & 2 & 4 & 6 & 8 \
P ( X = x ) & \frac { 9 } { 40 } & \frac { 6 } { 40 } & \frac { 1 } { 40 } & \frac { 24 } { 40 }
\end{array}$$    Round your answer to tenth if necessary.
A) $E ( X ) = 4$
B) $E ( X ) = 5$
C) $E ( X ) = 6$
D) $E ( X ) = 10$
E) $E ( X ) = 20$

Quizplus · Accepted Answer

The expected value $E(X)$ is calculated as $\sum x_i \cdot P(X = x_i)$. Here, $E(X) = 2 \cdot \frac{9}{40} + 4 \cdot \frac{6}{40} + 6 \cdot \frac{1}{40} + 8 \cdot \frac{24}{40} = 6$.

Find the Expected Value of a Random Variable X Having