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Choose the correct option.
Let X be a discrete random variable. The probability distribution of X is given below: X 30 10 -10…
Let $X$ be a discrete random variable. The probability distribution of $X$ is given below:
Then $E(X)$ will be:
| $X$ | $30$ | $10$ | $-10$ |
|---|---|---|---|
| $P(X)$ | $\frac{1}{5}$ | $\frac{3}{10}$ | $\frac{1}{2}$ |
- (a)$1$
- (b)$4$
- (c)$2$
- (d)$30$
Answer
Answer
Correct option: (b)
Answer: (b) $4$
$E(X)=30\cdot\frac15+10\cdot\frac3{10}-10\cdot\frac12=6+3-5=4$.