If the probability distribution of X is $\begin{array} { c c }
\mathrm { X } & \mathrm { P } ( \mathrm { X } ) \
3 & 1 / 8 \
4 & 1 / 8 \
5 & 3 / 8 \
6 & 3 / 8
\end{array}$
What is the expected value of X?
A)1.0
B)5.0
C)2.25
D)2.24

Question

If the probability distribution of X is $\begin{array} { c c } 
\mathrm { X } & \mathrm { P } ( \mathrm { X } ) \
3 & 1 / 8 \
4 & 1 / 8 \
5 & 3 / 8 \
6 & 3 / 8
\end{array}$
What is the expected value of X?
A)1.0
B)5.0
C)2.25
D)2.24

Quizplus · Accepted Answer

Expected value is calculated as follows:

E(X) = Σ[X * P(X)]

E(X) = (3 * 1/8) + (4 * 1/8) + (5 * 3/8) + (6 * 3/8)

E(X) = 3/8 + 4/8 + 15/8 + 18/8

E(X) = 40/8

E(X) = 5

Therefore, the expected value of X is 5, which is option B.

If the Probability Distribution of X Is XP(X)31/841/853/863/8\begin{array} { c c } \mathrm { X } & \mathrm { P } ( \mathrm { X } ) \\3 & 1 / 8 \\4 & 1 / 8 \\5 & 3 / 8 \\6 & 3 / 8\end{array}X3456​P(X)1/81/83/83/8​

If the Probability Distribution of X Is $\begin{array} { c c } \mathrm { X } & \mathrm { P } ( \mathrm { X } ) \\3 & 1 / 8 \\4 & 1 / 8 \\5 & 3 / 8 \\6 & 3 / 8\end{array}$