Q.
Let $X$ be discrete random variable. The probability distribution of $X$ is given below.
$X$
30
10
-10
$P(X)$
$\frac{1}{5}$
$\frac{3}{10}$
$\frac{1}{2}$
Then, $E(X)$ is equal to
| $X$ | 30 | 10 | -10 |
| $P(X)$ | $\frac{1}{5}$ | $\frac{3}{10}$ | $\frac{1}{2}$ |
Probability - Part 2
Solution:
Given that
$X$
30
10
-10
$P(X)$
$\frac{1}{5}$
$\frac{3}{10}$
$\frac{1}{2}$
$E(X)=30 \times \frac{1}{5}+10 \times \frac{3}{10}+(-10) \times \frac{1}{2}$
$=6+3-5=9-5$
$=4$
| $X$ | 30 | 10 | -10 |
| $P(X)$ | $\frac{1}{5}$ | $\frac{3}{10}$ | $\frac{1}{2}$ |