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Question
Let X be a discrete random variable. The probability distribution of X is given below:
| X | 30 | 10 | – 10 |
| P(X) | `1/5` | `3/10` | `1/2` |
Then E(X) is equal to ______.
Options
6
4
3
– 5
Solution
Let X be a discrete random variable. The probability distribution of X is given below:
| X | 30 | 10 | – 10 |
| P(X) | `1/5` | `3/10` | `1/2` |
Then E(X) is equal to 4.
Explanation:
E(X) = `30 xx 1/5 + 10 xx 3/10 - 10 xx 1/2` = 4.
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