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Question
Mark the correct alternative in the following question:
For the following probability distribution:
| X: | −4 | −3 | −2 | −1 | 0 |
| P(X): | 0.1 | 0.2 | 0.3 | 0.2 | 0.2 |
The value of E(X) is
Options
0
−1
−2
−1.8
Solution
The probability distribution of X is given below:
| X: | −4 | −3 | −2 | −1 | 0 |
| P(X): | 0.1 | 0.2 | 0.3 | 0.2 | 0.2 |
\[E\left( X \right) = \left( - 4 \right) \times 0 . 1 + \left( - 3 \right) \times 0 . 2 + \left( - 2 \right) \times 0 . 3 + \left( - 1 \right) \times 0 . 2 + 0 \times 0 . 2\]
\[ = - 0 . 4 - 0 . 6 - 0 . 6 - 0 . 2\]
\[ = - 1 . 8\]
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